Category: Aging trends

Can Learner Tien Hang With the Big Boys?

Learner Tien at the 2024 US Open. Credit: Hameltion

Learner Tien has done little in 2024 except win. He reeled off a 28-match streak from May to late July, collecting five titles, including his first at the Challenger level. He reached the quarter-finals at the tour event in Winston-Salem. After picking up two more Challenger crowns and another final, the young American opened his NextGen Finals campaign yesterday with a victory over top-50 player Jakub Mensik, 21st on the Elo list.

If you don’t follow prospects, you can be forgiven if you’ve only recently learned the name. Tien is only two weeks removed from his 19th birthday. He opened the year only barely inside the top 500. There were plenty of reasons to expect big things from the young man–a national 18s title at 16, two junior slam finals–but it would have been foolish to predict so much, so soon.

One reason to moderate expectations is simply age. For those not named Alcaraz or Sinner, it takes time to develop into a top player. Only one man under the age of 21–the cutoff for this week’s event in Jeddah–is ranked inside the top 40. Before Tien turned 19 this month, he was the top-ranked 18-year-old in the world, even with a triple-digit number next to his name.

The climb to the top is even more challenging for youngsters who can’t rely on pure power. Mensik, the highest-ranked teenager, is six feet, four inches tall, with weapons that make him seem bigger. Novak Djokovic recently called him “one of the best servers we have in the game.” The Czech has plenty to learn, and he will surely continue to refine his game. But to compete at the top level, he doesn’t have to.

Tien doesn’t have that luxury. He stands five inches shorter than Mensik. While he may have a bit more growth coming, five-eleven is near the bottom edge of what can be managed on the ATP tour. Only 15 members of the top 100 stand less than six feet, and even that list is skewed toward clay-court specialists. Sebastian Baez is the only five-foot-anything ranked above 45th.

The playing styles available to shorter athletes are limited, especially on hard courts. Tien has already demonstrated his mastery of many of those tactics. He can use his left-handedness to swing serve after serve wide, to a righty’s backhand. He is sturdy from the baseline, and you can take that literally: He’s unafraid of claiming territory right up to the line itself, taking advantage of both his quickness and raw speed. Fearless counterpunching has paid dividends for smaller stars from Olivier Rochus to Kei Nishikori to Alex de Minaur. As a lefty, the American has options those men didn’t.

Still, Tien’s transition from the Challenger tour to the big leagues could be rocky. Good defense and well-executed tactics are enough to clean up against top-200 competition. The combination was (just barely) sufficient against Mensik yesterday. But a full-time spot on the ATP tour requires more.

The game plan

For such a middling server, Tien wins a remarkable number of serve points. He ranks among the top quarter of Challenger tour regulars by serve points won, though his number is helped a bit by spending the entire year on hard courts. He does even better–64.6% compared to a tour norm below 62%–when aces and double faults are taken out of the equation. When the returner gets a racket on the ball, only ten players were better on hard courts.

It’s not surprising, then, that Tien excels on return. Among Challenger players with at least ten matches at the level in 2024, only two men–Dalibor Svrcina and his fellow American in Jeddah, Nishesh Basavareddy–topped Learner’s 42.5% clip. Tien is particularly effective converting second-serve return points.

He’s even better–or at least, he has been better this season–with more on the line. His rate of return points won rises to nearly 47% on break point chances, and he’s just as clutch on the other side of the ball. He saved 65.6% of the break points he faced, second at Challenger level to Mikhail Kukushkin. Here, he has already learned how to use the lefty serve, alternately forcing opponents far out wide and sticking them with uncomfortable body serves when he catches them leaning left for the slider.

The overall package is something between those of two other left-handers, Adrian Mannarino and Cam Norrie. Mannarino, also a sub-six-footer, throws the kitchen sink at opponents, keeping them off balance to compensate for his own lack of power. Norrie is considerably taller and has more firepower at his disposal. But he, too, refuses any rhythm to the man across the net. He alternates a loopy forehand with a flat backhand–except when he doesn’t, if you ever think you’ve found a groove.

Tien serves like Mannarino out of necessity. Even if he doesn’t get taller, the American will surely get stronger, so his 90-mile-per-hour first serves from this year’s US Open probably won’t tell the story of his entire career. But at the moment, he relies on angles and variety. Mannarino has overcome his limitations to the tune of a top-20 peak ranking. On the other hand, his playing style (and the comically loose string tension it relies on) is so unique he hardly provides an example to follow.

In the Las Vegas Challenger final back in September, Tien looked particularly like Norrie. Fighting the wind, he spun forehands and zinged backhands, a combination that made it impossible for the bigger-hitting Tristan Boyer to get comfortable. In other settings, though, the youngster is increasingly using his forehand as a (flatter) weapon, building points one sharp angle at a time.

The most instructive element of these comparisons, though, is the way in which the American differs from his fellow lefties. Mannarino reached Tien’s current ranking when he was 21, after more than 250 pro matches. Norrie–who ultimately peaked inside the top ten–played three years of college tennis and didn’t approach the top 100 in the world until he was 22. Tien, by contrast, is clearing all these hurdles on the first try. Deploying a brainy playing style that normally takes years to refine, the American is making it look natural.

The projection

Aside from size and serve speed, Tien’s future looks bright. The 19-year-old has won 61 of 73 matches across all levels this year. Within a few months, he is likely to crack the top 100. At Challenger level, his serve hasn’t held him back: As we’ve seen, he wins more service points than most of his peers, despite gaining fewer free points with the serve itself.

The question, then, is what effect Tien’s attributes have on career trajectory. Everyone wins fewer points at tour level than at Challengers–the competition is better, so it would be weird if it were otherwise. But the ratio isn’t uniform. Mannarino has won about 7% fewer serve points at tour level than he did in hard-court Challenger matches, while Marcos Giron (another sub-six-footer) lost less than 1% in the transition.

These Challenger-to-tour conversions offer some insight into Learner’s future. Since he has played almost all of his pro matches on hard courts, we’re going to calculate something a bit quirky. How do serve and return win rates change from hard-court Challenger matches to all tour-level matches? That’s what we want to know for the 19-year-old: He’ll need to play on all surfaces soon, probably starting in 2025. This transition he’s about to make–how did it go for other players?

The first-pass answer is that pros are able to retain something like their hard-court Challenger serve win percentage, seeing that number drop by 2%. But they lose a lot against tougher competition on return, winning 7.1% fewer return points. The following table shows those numbers (“Conv%”), along with Tien’s career record at hard-court Challengers (“Tien CH”), along with what the conversion factors suggest for his tour-level win rates (“Tien Adj”):

        Conv%  Tien CH  Tien Adj  
Serve   98.0%    63.3%     62.0%  
Return  92.9%    42.3%     39.3%

Those are awfully respectable numbers. 62% serve points is marginal for a tour regular, but combined with 39.3% return points, it’s enough. The combination is about what Francisco Cerundolo managed this year, and he’s ranked 30th in the world.

A word of caution: This type of conversion is not suggesting that Tien’s level is the same as Cerundolo’s now. The calculation involves taking each active player’s career records in tour and Challenger main-draw matches. That probably underestimates Tien’s potential, because most men play the majority of their Challenger matches after their 19th birthday. But a player’s career numbers will include their peak, which typically comes much later. At the very least, these numbers suggest Tien could reach Cerundolo’s level (or better) eventually.

The (other) adjustments

That’s just a first-pass number, because we haven’t gotten to height and handedness. Taking those into account does not help Learner’s case.

Lefties, it turns out, have a rougher transition than right-handers do. Here are the serve and return conversion factors, separated by hand:

        Lefties  Righties  
Serve     97.3%     98.1%  
Return    92.1%     93.0%

Not a huge difference, but hey, the margins in tennis are small. I suspect it is slightly harder for left-handers to move up a level for two reasons. First, the less experienced the opponent, the more valuable it is to be unusual, and lefties are certainly that, making up barely one-tenth of the player pool. At tour level, the novelty is gone: ATP regulars generally know how to handle left-handers.

Second, lefties are more likely to get by with what we might call “crafty” tennis, rather than power. (That’s related to the first reason: They’ve reached Challenger level because they’ve outsmarted inexperienced opponents thus far.) Craftiness might be enough against #180 in the world, but against, say, the Hurkacz serve, all craftiness gets you is a few more tuts of approval in the press box.

Whatever the reason, Tien’s left-handedness means we need to update our tour-level forecast:

    (L) Conv%  Tien CH  Tien Adj  
Serve   97.3%    63.3%     61.6%  
Return  92.1%    42.3%     39.0%

Not a huge hit, but ~0.4% of total points won is roughly equivalent to four places in the rankings. A small number here ultimately translates to much bigger ones when denominated by tour-level prize money.

And then, size. Here are the conversion factors for players in three height categories: under six feet, from six feet to six-foot-three, and above six-foot-three:

        under 6'0  6'0 to 6'3  over 6'3  
Serve       97.0%       97.9%     99.0%  
Return      92.0%       93.4%     92.6%

Again, craftiness doesn’t convert. Players under six feet tall lose the most points between hard-court Challengers and tour level. The tallest players remain almost as effective on serve, while the middle category retains the most of their return effectiveness.

Here’s the Tien update, using the sub-six-feet conversion rates:

        (< 6') Conv%  Tien CH  Tien Adj  
Serve          97.0%    63.3%     61.4%  
Return         92.0%    42.3%     38.9%

Not much of a difference from the left-handed numbers, though we keep going down. This is increasingly the profile of a clay-court specialist, and we might be outside the top 40 now.

Of course, Learner is both left-handed and (relatively) small. My mini-study of active players doesn't give us a big enough pool of data to extrapolate from the small group of small lefties. Instead, a back-of-the-envelope combination of the two factors gives us conversion factors of 96.3% for serve and 91.3% for return:

        (L&Sm) Conv%  Tien CH  Tien Adj  
Serve          96.3%    63.3%     61.0%  
Return         91.3%    42.3%     38.6%

For the first time, the adjusted versions of Tien's Challenger-level stats are underwater, summing to less than 100%. Winning 61% of service points would rate fourth-worst in the current ATP top 50, just ahead of Sebastian Baez. 38.6% on return is respectable, though not enough to consistently challenge for titles when combined with such a mediocre serve.

The exact numbers are not important: For one thing, we don't have enough recent data to know exactly how size and handedness interact. Maybe it's not quite that bad. Suffice it to say that both lefties and undersized players are more likely to struggle in the transition from Challengers to the full tour. A player who fits both categories should not expect a smooth trip up the ladder.

For Tien to beat these projections, all he has to do is improve more than the average pro does. As noted above, he already has something of an edge: He posted most of his excellent Challenger numbers as an 18-year-old. That's Alcaraz territory. At the same age, Mannarino was struggling at Futures level, and future top-tenner Norrie was headed off to college. If for some reason Tien plays a lot of Challenger matches in 2025, his stats will probably look better, and the tour-level predictions would change as well.

As Learner and his team are undoubtedly aware, those improvements need to center on the serve. The youngster probably already has what it takes to break serve once or twice a set on tour. But without a bigger first-strike weapon, he'll struggle to get those opportunities. Yesterday he withstood Jakub Mensik's event-record 24 aces, winning in a fifth-set tiebreak despite losing 14 more total points than Mensik did. The American played brilliant tennis, yet it took luck and brilliant timing to pull out the victory. For a five-foot-eleven left-hander among the giants of the professional game, it's not the last tightrope he'll have to walk.

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Mirra Andreeva’s Many Happy Returns

Mirra Andreeva at the 2024 Paris Olympics.
Credit: Like tears in rain

Mirra Andreeva is the best teenager on the WTA tour, and it isn’t close. She’ll finish 2024 ranked 16th on the official points table, more than one hundred places ahead of her closest teenage competitor, Maya Joint. Andreeva is a year younger than Joint, and she’s two years younger than Ella Seidel, third on the under-20 list.

Players who outpace their fellow teenagers typically go on to notable careers. Here’s the list of top teenagers at the end of each season this century:

Year  Player                    Rank  
2000  Serena Williams              6  
2001  Kim Clijsters                5  
2002  Kim Clijsters                4  
2003  Vera Zvonareva              13  
2004  Maria Sharapova              4  
2005  Maria Sharapova              4  
2006  Maria Sharapova              2  
2007  Nicole Vaidisova            12  
2008  Agnieszka Radwanska         10  
2009  Caroline Wozniacki           4  
2010  Anastasia Pavlyuchenkova    21  
2011  Christina McHale            43  
2012  Sloane Stephens             38  
2013  Eugenie Bouchard            32  
2014  Madison Keys                30  
2015  Belinda Bencic              14  
2016  Daria Kasatkina             26  
2017  Catherine Bellis            46  
2018  Dayana Yastremska           58  
2019  Bianca Andreescu             5  
2020  Iga Swiatek                 17  
2021  Emma Raducanu               19  
2022  Coco Gauff                   7  
2023  Coco Gauff                   3  
2024  Mirra Andreeva              16

There’s no such thing as a can’t-miss prospect in women’s tennis, but showing up on this list gets you pretty close. Andreeva’s case is particularly extreme, because she is still just 17 years old.

In the under-18 category, the young Russian has virtually no competition. Only three other under-18s rank among the top 200, none closer than Alina Korneeva at 176th. No woman so young has finished inside the top 20 in almost two decades, going back to Nicole Vaidisova’s top-ten showing in 2006.

Here’s another way to look at what Andreeva has accomplished. With four victories to reach the Ningbo final in October, she increased her career tour-level main-draw win count to 48. Take a look at the list of all women, post-Vaidisova, to post even 30 such wins before their 18th birthday:

Wins  Player              Last Win as 17yo  
32    Victoria Azarenka         2007-07-30  
47    Caroline Wozniacki        2008-06-23  
42    Tamira Paszek             2008-09-15  
32    Donna Vekic               2014-06-23  
33    Amanda Anisimova          2019-07-29  
64    Coco Gauff                2022-03-07  
48    Mirra Andreeva            2024-10-14

Again, good company, and think of all the stars who aren’t here. You know, everybody (besides Vekic) for a decade. In this entire time span of about 17 years, Andreeva has done more at her age than anyone except Coco Gauff. The Russian might even erase that caveat. She doesn’t turn 18 until the end of April, and this year, she had won 12 matches by that time. 17 wins–enough to surpass Gauff–is hardly out of reach.

Let’s turn now to how Andreeva is achieving so much success, and why she might soon lop a digit off of her age-defying ranking.

Returns first

Forget about all this under-18 and teenager stuff for a minute. Mirra is already one of the best returners in the game. Here are the top dozen WTA tour regulars, ranked by return points won:

This isn’t a perfect measure. For one thing, Andreeva faced one of the weaker schedules of players on this list. Her median opponent was ranked 58th, compared to 30th for Iga and 42nd for Coco. It would take considerably more work to suss out whether Andreeva’s 47.3% of return points won, against her set of opponents, is better or worse than, say, Aryna Sabalenka’s 45.3% against competition nearly as stiff as Swiatek’s.

The quibbles mean that we can’t quite proclaim the Russian a top-three returner. The point, though, is that she’s in the conversation. In fact, if we narrow our view to matches against top-20 players–limiting if not eliminating the influence of each woman’s schedule–Andreeva hangs on to her position:

(We’re not talking about Iga today, but… 47% of return points won against top-20 opponents? My word.)

Where Andreeva shines even brighter is against first serves. She won first-serve return points at a higher clip than any other woman on tour this year:

Player               1st RPW%  
Mirra Andreeva          42.6%  
Coco Gauff              42.1%  
Marketa Vondrousova     40.8%  
Iga Swiatek             40.8%  
Daria Kasatkina         40.7%  
Marta Kostyuk           40.5%  
Elina Avanesyan         40.0%  
Jasmine Paolini         40.0%  
Katerina Siniakova      39.5%  
Karolina Muchova        39.5%

Put that in perspective: Andreeva wins more first-serve return points than Barbora Krejcikova (to pick one name from several) wins all return points.

Again, the Russian’s stats are influenced by her level of competition. Against top-20 opponents, Mirra falls to third place, behind Swiatek and just back of Gauff. But you get the idea. To say, “Well, actually, she’s not quite up to Gauff’s standard” is to say we’re dealing with a special player.

Precocious patience

Andreeva’s serve is good for a 17-year-old, but as we’ve seen, it’s not the side of her game that has put her in the top 20. Her returns, and by extension, her baseline play, are responsible for that.

Among top players, Mirra is currently most similar to countrywoman Daria Kasatkina. The two Russians, according to Match Charting Project data, post average rally lengths of 4.9 strokes, more than anyone else in the top 40. Both women are effective off both wings; Andreeva’s backhand is the better of the two, while Kasatkina’s forehand scores more points. The teenager is a bit more likely to force the issue: While both rank well below average in Rally Aggression Score, Mirra is closer to the norm.

A key difference shows up in their rally breakdowns. Again based on the subset of matches logged by the Match Charting Project, here are each woman’s percent of points won at various rally length categories:

Player     1-3 W%  4-6 W%  7-9 W%  10+ W%  
Andreeva    49.8%   48.6%   51.8%   53.8%  
Kasatkina   48.0%   45.6%   51.0%   52.5%

The first thing that pops out here is that Andreeva is better in every category, something that reflects both the vagaries of the uneven tennis schedule and the non-random nature of Match Charting Project samples. However you slice it, Mirra won more points, though my Elo rankings agree with the official formula that Kasatkina was the better player.

To get a better idea of what we’re looking at, let’s normalize each woman’s rally-category splits as if they won exactly half of their overall points:

Player     1-3 W%  4-6 W%  7-9 W%  10+ W%  
Andreeva    49.5%   48.3%   51.5%   53.5%  
Kasatkina   49.6%   47.1%   52.7%   54.2%

The teenager holds the edge in the 4-6-stroke category, while Kasatkina looks better in the longer rallies.

That 4-6-shot category tells us more than it lets on. Andreeva’s 48.3% (or the un-normalized 48.6%) doesn’t look very impressive. Points in this group account for one quarter of all the points she plays, and she loses more than half.

But consider her playing style. Medium-short rallies are often determined by the lingering influence of the serve: The returner might withstand a plus-one attack, only to leave a sitter for the server to put away. Or a strong return doesn’t finish the point, but the returner’s next shot–the fourth stroke of the rally–does the job. 4-6-shot rallies go disproportionately to big hitters: Aryna Sabalenka led the category this year.

For someone like Andreeva or Kasatkina, the task is to limit the damage. Get the serve back, try to neutralize the point. Place serves where aggressive returners won’t do too much damage. If a big return comes back, play the same defense that works against the serve. Kasatkina has all of those skills, but there is only so much she can do. Mirra, with her flatter strokes and somewhat bigger weapons, can keep opponents from running away with these medium-short points. She’ll lose sometimes to the likes of Sabalenka, but unless they catch her on an off day, she won’t be blown off the court.

Growth potential

If Andreeva could be characterized as a younger, somewhat more aggressive Kasatkina, that would be a pretty good compliment for a 17-year-old. But the teenager promises to become much more.

One of my favorite bits of counterintuitive tennis wisdom is that return stats rarely improve. Returning is based on a set of skills–anticipation, quickness, speed–that, on net, decline with age. Whatever tactical savvy a player picks up as she ages will, at best, cancel out the age-related decline. This isn’t an iron law, but it’s surprising how often players reach their peak return effectiveness very early in their careers.

The same is not true for the serve. 17-year-olds (or, hey, 23-year-olds) have the capacity to get stronger. Footspeed and reaction time don’t figure into the serve, so with better coaching or targeted practice (think late-career Djokovic), serve stats can improve even as the rest of a player’s game declines. A couple of examples: Maria Sakkari steadily improved her first-serve win rate from the 13th percentile to the 93rd percentile in five years. Simona Halep’s first-serve was in the top quarter of tour regulars in 2014; two years earlier, it had been one of the WTA’s worst.

The implications for Andreeva are clear. We don’t need to wishcast an improvement in her return game: She’s already one of the best returners in the game. Instead, the road to the top ten and beyond goes through her serve. Her results so far are adequate. She won 58.4% of her serve points in 2024, compared to a top-50 average of 58.7%. When we consider how much she played on clay, that number looks a bit better. On hard courts, she won more serve points than average.

Mirra, then, doesn’t face the same uphill struggle that Sakkari and Halep overcame. Her potential trajectory is more like, say, Victoria Azarenka’s. Vika arrived on the scene as a killer returner with a good-enough serve. In 2009 and 2010, she won nearly half of her return points against 58% to 59% of her service points. That combination earned her two top-ten finishes. (She was a few years older than Andreeva at that point, yet another reminder of how unique the Russian’s early success has been.)

Two years later, Azarenka boosted her rate of serve points won to 61%. Combined with the same results on return that had gotten her into the top ten, the bigger serve earned her six titles–including her first major–and the year-end number one ranking. 59% to 61% may not sound like much, but for an elite returner, that’s all it takes.

If Andreeva did the same, lifting her 58.4% serve-point win rate to 61%, she’d be the ninth-best server on tour. Remember how she’s just a tick behind Coco Gauff on return? A Vika-like serve boost would put her ahead of the American in that category, outweighing Coco’s narrow edge on return. Shorter version: She’d be a top-three player, maybe more.

None of this is guaranteed. It may not–it probably won’t!–happen right away. For every Azarenka, there’s a Nicole Vaidisova or, worse, an injury victim like Catherine Bellis. Still, few paths to the top are marked so clearly. For Mirra Andreeva, a modest, achievable set of improvements are all that stand between her and the top.

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What Is Going Wrong For Novak Djokovic?

Also: Arina Rodionova (probably) in the top 100

Novak Djokovic practicing at the 2023 US Open. Credit: Amaury Laporte

Fifteen break points. A week has passed, a new champion has been crowned, and I still can’t stop thinking about it. In the first two sets of his Australian Open quarter-final match against Taylor Fritz, Novak Djokovic failed to convert fifteen straight break points.

It’s so far out of character as to defy belief. Djokovic has converted more than 40% of his break chances in the past year, even counting the 4-for-21 showing in the entire Fritz match. The American, one of the better servers on tour, typically saves only two-thirds of the break points he faces. The chances that Novak would come up short 15 times in a row are about one in seven million.

Even stranger, it wasn’t because Fritz served so well. He missed his first serve on 7 of the 15 break points. He hit two aces and another four didn’t come back, but that leaves nine rallies when–under pressure, in Australia–Taylor Fritz beat Novak Djokovic. Five of those lasted at least seven strokes, including a 25-shot gutbuster at 4-3 in the second set that was followed, two points later, by yet another Fritz winner on the 17th shot. All credit to the American, who walked a tightrope of down-the-line backhands and refused to give in to an opponent who, even in the first two sets, was outplaying him. But clearly this wasn’t a matter of Fritz intimidating or otherwise imposing himself on Novak.

There’s no shortage of explanations. Djokovic is recovering from a wrist injury that hampered him in his United Cup loss to Alex de Minaur. He apparently had the flu going into the Melbourne semi against Jannik Sinner. The whole Australian adventure might be nothing more than a health-marred aberration; in this interpretation, none of Jiri Lehecka, Dino Prizmic, Alexei Popyrin, or even Fritz would otherwise have taken a set from the all-time great.

But… the man is 36 years old. If other tennis players his age are any guide, he may never be fully healthy again. He will continue to get slower, if only marginally so. He personally raised the physical demands of the sport, and finally, a younger generation has accepted the challenge. Djokovic has defied the odds to stay on top for as long as he has, but eventually he will fade, even if that means only a gentle tumble out of the top three. After a month like this, we have to ask, is it the beginning of the end?

Rally intolerance

The two marathon break points that Fritz saved were not exceptions. 64 of the 269 points in the quarter-final reached a seventh shot, and the American won more than half of them. Even among double-digit rallies, the results were roughly even.

Here’s another data point: Djokovic fought out 53 points in his first-rounder against Prizmic that reached ten shots or more. The 18-year-old Croatian won 30 of them. Yeah, Prizmic is a rising star with mountains of potential, but he’s also ranked 169th in the world. This is not the Novak we’ve learned to expect: Even after retooling his game around a bigger serve and shorter points, he remained unshakeable from the baseline, his famous flexibility keeping him in position to put one more ball back in play.

Down Under, though, those skills went missing. Based on 278 charted matches since the start of 2015, the following table shows the percentage of points each year that he takes to seven shots or more, and his success rate in those rallies:

Year  7+ Freq  7+ Win%  
2015    23.3%    54.9%  
2016    26.7%    53.1%  
2017    29.1%    53.3%  
2018    24.4%    52.6%  
2019    25.0%    55.1%  
2020    26.0%    54.3%  
2021    23.8%    53.6%  
2022    23.2%    54.7%  
2023    23.4%    54.1%  
2024    26.0%    49.8%

By the standards of tennis’s small margins, that’s what it looks like to fall off a cliff. The situation probably isn’t quite so bad: The sample from 2024 is limited to only the matches against Lehecka, de Minaur, Prizmic, Fritz, and Sinner. On the other hand, matches charted in previous years also skew in favor of novelty, so upsets, close matches, and elite opponents are overrepresented there too.

It is especially unusual for Djokovic to see such a decline on hard courts. Over the last decade, he has gone through spells when he loses more long rallies than he wins. But they typically come on clay. Carlos Alcaraz shut him down in last year’s Wimbledon final as well, winning 57% of points that reached the seventh shot and 63% of those with ten or more strokes. The only period when hard-court Novak consistently failed to win this category was late 2021, when Medvedev beat him for the US Open title (and then outscored him in long rallies in Paris), and Alexander Zverev won 62% of the seven-plusses (and 70% of ten-plusses!) to knock him out of the Tour Finals.

Protracted rallies are a young man’s game, and Djokovic’s results are starting to show it. Before dissecting Alcaraz in Turin last November, Novak had never won more than half of seven-plusses against Carlitos. He has barely held on against Sinner, winning 43% of those points in their Tour Finals round-robin match and 51% at the Davis Cup Finals. In 13 meetings since 2019, Medvedev has won more of these long rallies than Djokovic has. Zverev, too, has edged him out in this category since the end of 2018.

Against the rest of the pack, Djokovic manages just fine. He dominates seven-plusses against Casper Ruud and Stefanos Tsitsipas, for instance. But it’s one of the few chinks in his armor against the best, and if January represents anything more than the temporary struggles of an ailing star, more players are figuring out how to take advantage.

Avoiding danger

For players who lose a disproportionate number of long points, the best solution is to shorten them. Djokovic may never have thought in exactly those terms, but perhaps with an eye toward energy conservation, he has done exactly that.

Especially from 2017 to 2022, Novak drastically reduced the number of points that reached the seven-shot threshold:

In 2017, 29% of his points went that long; in 2022 and 2023, barely 23% did. It remains to be seen whether January 2024 is more than a blip. In his up-and-down month, Novak remained able to control his service points, but he was less successful avoiding the grind on return. As we’ve seen, that’s dangerous territory: Djokovic won a healthy majority of the short points against Fritz but was less successful in the long ones, especially following the American’s own serve.

Much rests on the direction of these trends. If the players Djokovic has faced so far this year can prevent him from finishing points early, how will he handle Medvedev or Zverev?. If Novak can’t reliably outlast the likes of Fritz and Prizmic, what are his chances against Alcaraz?

Djokovic is well-positioned to hold on to his number one ranking until the French Open, when he’ll be 37 years old. By then, presumably, he’ll be clear of the ailments that held him back in Australia. Still, holding off the combination of Sinner, Alcaraz, Medvedev, Zverev, and Father Time will be increasingly difficult. The 24-time major champion will need to redouble the tactical effort to keep points short and somehow recover the magic that once made him so implacable in the longest rallies. Age is just a number, but few metrics are so ruthless in determining an athlete’s fate.

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Arina Rodionova on the cusp of the top 100

In December, Australian veteran Arina Rodionova celebrated her 34th birthday. Now she’s competing at the tour-level event in Hua Hin this week, sporting a new career-best ranking of 101. With a first-round upset win over sixth-seed Yue Yuan, she’s up to 99th in the live rankings. Her exact position next Monday is still to be determined–a few other women could spoil the party with deep runs, or she could climb higher with more victories of her own–but a top-100 debut is likely.

Rodionova, assuming she makes it, will be the oldest woman ever* to crack the top 100 for the first time. The record is held by Tzipi Oblizer, who was two months short of her own 34th birthday when she reached the ranking milestone in 2007. Rodionova will be just the fifth player to join the top-100 club after turning 30.

* I say “ever” with some caution: I don’t have weekly rankings before the mid-80s, so I checked back to 1987. Before then, the tour skewed even younger, so I doubt there were 30-somethings breaking into the top 100. But it’s possible.

Here is the list of oldest top-100 debuts since 1987:

Player                    Milestone  Age at debut  
Arina Rodionova*         2024-02-05          34.1  
Tzipi Obziler            2007-02-19          33.8  
Adriana Villagran Reami  1988-08-01          32.0 
Emina Bektas             2023-11-06          30.6  
Nuria Parrizas Diaz      2021-08-16          30.1  
Mihaela Buzarnescu       2017-10-16          29.5  
Julie Ditty              2007-11-05          28.8  
Eva Bes Ostariz          2001-07-16          28.5  
Maryna Zanevska          2021-11-01          28.2  
Ysaline Bonaventure      2022-10-31          28.2  
Mashona Washington       2004-07-19          28.1  
Laura Pigossi            2022-08-29          28.1  
Maureen Drake            1999-02-01          27.9  
Hana Sromova             2005-11-07          27.6  
Laura Siegemund          2015-09-14          27.5

* pending!

I extended the list to 16 places in order to include Laura Siegemund. She and Buzarnescu are the only two women to crack the top 100 after their 27th birthdays yet still ascend to the top 30. The odds are against Rodionova doing the same–the average peak of the players on the list is 67, and the majority of them achieved the milestone a half-decade earlier–but you never know.

A triumph of scheduling

Rodionova has truly sweated her way to the top. She played 105 matches last year, winning 78 of them, assembling a haul of seven titles and another three finals. When I highlighted the exploits of Emma Navarro a couple of weeks ago, I couldn’t help but draw attention to the Australian, who is one of only two women to win more matches than Navarro since the beginning of last year. Iga Swiatek is the other.

Most of the veteran’s recent triumphs–44 match wins and five of her seven 2023 titles–have come at the ITF W25 level. She didn’t beat a single top-200 player in those events, and she faced only five of them. In her long slog through the tennis world last year, Rodionova played just one match against a top-100 opponent, and that was a loss to 91st-ranked Dalma Galfi.

The point is, the Aussie earned her ranking with quantity, not quality. No shame in that: The WTA made the rules, and the Australian not only chose a schedule to maximize her chances of climbing the ranking table, she executed. Kudos to her.

What her ranking does not mean, however, is that she is one of the 100 best players in the world. Elo is a more reliable judge of that, and going into this week, the algorithm ranks her 207th. (She peaked in the 140s, back in 2017.) You can hack the WTA rankings with a punishing slate of ITFs, but it’s much harder to cheat Elo.

Here are the players in the official top 150 who Elo considers to be most overrated:

Player             Elo Rank  WTA Rank  Ratio  
Caroline Dolehide       124        41    3.0  
Peyton Stearns          145        54    2.7  
Arantxa Rus             103        43    2.4  
Tatjana Maria            94        44    2.1  
Arina Rodionova         207       101    2.0  
Laura Pigossi           221       114    1.9  
Elina Avanesyan         120        62    1.9  
Varvara Gracheva         89        46    1.9  
Nadia Podoroska         127        67    1.9  
Lucia Bronzetti         109        58    1.9  
Dayana Yastremska        54        29    1.9

Once you climb into the top 100, savvy scheduling is increasingly impractical. Instead, this kind of gap comes from a deep run or two combined with many other unimpressive losses. Caroline Dolehide reached the final in Guadalajara followed by a quarter-final exit at a WTA 125, then lost three of five matches in Australia. Arantxa Rus won the title in Hamburg and reached a W100 semi-final, then lost five of six. The WTA formula lets you keep all the points from a big win for 52 weeks; Elo takes them away if you don’t keep demonstrating that you belong at the new level.

The sub-200 Elo rank suggests that Rodionova will have a hard time sustaining her place on the WTA list once the ranking points from her W25 titles start to come off the board. Until then, she can continue to pad her total and–fingers crossed–enjoy the hard-earned reward of a double-digit ranking.

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The Improbable Rise of Emma Navarro

Also today: New stat leaderboards

Emma Navarro at the 2023 US Open. Credit: Hameltion

When Emma Navarro beat Elise Mertens for her first WTA title in Hobart on Saturday, it was only part of a natural progression. For more than a year now, she has shown a knack for winning, regardless of level, surface, or just about anything else. While most fans still don’t know her name, she’s up to 26th in the official rankings and 22nd on the Elo list.

The former collegiate champion–winner of the national title as a Virginia Cavalier in 2021–started her 2023 campaign just inside the top 150. She arrived at the brink of the top 100 with back-to-back ITF titles on clay in April, then cracked the top 60 with a grass-court final in Ilkley. Her first top-ten win came in September on hard courts, against Maria Sakkari in San Diego, and after a busy fall that included another two ITF titles, she broke into the top 40. She’s 8-1 so far in 2024; the only blip is a loss to Coco Gauff.

Altogether, that’s 72 victories since the beginning of last year. Not many women can boast so much success at the W25 level or higher in that span:

Player                   2023-24 Wins  
Arina Rodionova                    79  
Iga Swiatek                        73  
Emma Navarro                       72  
Oceane Dodin                       64  
Jessica Pegula                     62  
Julia Riera                        59  
Aryna Sabalenka                    59  
Martina Capurro Taborda            59  
Yafan Wang                         58  
Carlota Martinez Cirez             57

The remarkable part of Navarro’s rise is not the sheer quantity of positive results; it’s that she rose through the rankings so fast at the age she did. She first cracked the top 100 last May just before her 22nd birthday–hardly old by any rational standards, but nearly geriatric on the youth-driven WTA tour. The 25 players standing in front of Navarro in this week’s rankings broke into the top 100, on average, before their 20th birthday: The median is Aryna Sabalenka’s arrival at 19 years, 5 months. Late developers like Jessica Pegula, Barbora Krejcikova, and Navarro are exceptions to a long-standing rule.

It’s not unusual for a player to finally achieve a double-digit ranking when they are 21 or older, but it’s rare for a future star to do so–and now that Navarro is a tour-level title-holder ensconced in the top 30, she deserves that label. Since 1990, there have been 207 players who finished their age-21 season ranked between 101 and 200 without a previous appearance in the top 100. Only 25 of them reached #100 at the end of the following year; Navarro was only the fourth to crack the top 50.

Of those 200-plus players, only 35 of them ever achieved a top-40 ranking. (A few more, including Katie Boulter and Katie Volynets, could still join the group.) On average, it took them 1437 days–just short of four years–to do so. Navarro needed only 315 days, the second-fastest in the last 30-plus years. Here are the players who made the fastest move from the end of their age-21 season to the top 40:

Player                 Age 21  top 40 debut  Days  
Elise Mertens            2016    2017-08-28   245  
Emma Navarro             2022    2023-11-06   315  
Veronika Kudermetova     2018    2019-11-11   315  
Kurumi Nara              2012    2014-06-09   525  
Jamie Hampton            2011    2013-06-24   546  
Casey Dellacqua          2006    2008-07-28   581  
Tathiana Garbin          1998    2000-09-25   637  
Liudmila Samsonova       2019    2021-11-01   672  
Bethanie Mattek Sands    2006    2008-11-03   679  
Anne Kremer              1996    1999-04-12   833  
Jil Teichmann            2018    2021-04-26   847  
Zi Yan                   2005    2008-05-05   861  
Paula Badosa             2018    2021-05-24   875  
Yone Kamio               1992    1995-06-12   896  
Alison Riske Amritraj    2011    2014-06-09   896  
Johanna Konta            2012    2016-02-01  1127

It’s possible that Navarro could have been ready for the big time earlier had she not spent two years playing college tennis. Her sub-100 ranking at the end of 2022 was partly due to a limited schedule, as she played only a handful of tournaments before leaving school after the spring semester that year. But she wasn’t playing top-100 tennis when she did step on court: Elo ratings respond much more quickly to quality results (and do not reward quantity for its own sake), and her ranking by that algorithm, 148th, was virtually identical to her place on the official list.

Whatever the benefits and (temporary) costs of her stay at the University of Virginia, Navarro seemed to learn from the step up in competition–and quickly. She lost her first 11 matches against the top 50; in the last four months, she has won 5 of 6.

What works

The most memorable victory so far was Saturday’s triumph over Mertens for a debut WTA title. It was a grind, taking two hours, 50 minutes, and spanning 14 breaks of serve en route to a 6-1, 4-6, 7-5 finish. There was little first-strike tennis on display, as the average point ran to 5.5 strokes. 69 points required seven shots or more, and 37 reached double digits.

The battle for openings worked to Navarro’s advantage. In a sample of eleven previous matches logged by the Match Charting Project, she struggled in longer rallies, winning just 46% of points that reached a seventh shot compared to 49% overall. On Saturday, she reversed that trend in a big way, out-point-constructing her veteran opponent and winning a whopping 59% of the longer points. Of 84 charted Mertens matches, it was only the eighth time that she played at least 20 long points and won so few of them. Among the few players to beat her so soundly on rally tactics: Pegula and Simona Halep.

While Navarro’s results have steadily improved, her game plan is still recognizable form her days as a college champion. After defeating Miami’s Estrela Perez-Somarriba for the 2021 NCAA title, she described her approach: “I was able to dictate with my forehand and finish a lot of points with my backhand.” In Hobart, her backhand continued to populate the highlight reel, with seven clean down-the-line winners. But it was the forehand that opened the court in the first place.

She played, essentially, a clay-court match, using the forehand to create opportunities for the next ball. She hit winners with 7% of her forehand groundstrokes, slightly below tour average. But when she was able to hit a forehand, she won the point 62% of the time, an outstanding figure for a close match. One point serves as an illustration of the rest: At 2-all, 15-all in the third set, Navarro converted a return point with a down-the-line backhand winner on the 14th shot of the rally. After a deep forehand return, Navarro was forced to hit two backhands. When she was finally able to deploy the forehand on the 8th shot, she stabilized the point by going down the middle. The 10th shot took advantage of a let cord with a heavy crosscourt forehand, a weapon that worked in her favor on Saturday more than two-thirds of the time. Her next forehand went the other direction, creating the space for–finally–a backhand out of the Belgian’s reach.

While not every point was quite so tactical, point construction always lurked. Mertens frequently attempted a pattern where she would go the same direction with two consecutive groundstrokes then, having wrong-footed Navarro with the second of them, go for a winner. The sequence doesn’t work against a big swinger because the points don’t last long enough. That wasn’t a problem against the American, but Navarro’s resourcefulness nullified the tactic nonetheless. Unlike many players her age, Navarro is able to use slices off both wings to neutralize points, and she often did so on the second shot of Mertens’s would-be pattern. The Hobart champion hit 40 slices over the course of the match, ultimately winning the point on 20 of them. For a defensive shot, rescuing 50% of those situations counts as a victory.

There is little in Navarro’s game that advertises her as a world-beater: The weapons I’ve described work best as part of a carefully-managed package. She may prove to be most dangerous on clay, where aggressive opponents will have a harder time keeping points short. She might also develop yet another level. Twelve months ago, only a reckless forecaster would have predicted she could rise so high, so quickly. We still haven’t seen her peak.

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Deep leaderboards

Among the cult favorites on the Tennis Abstract site are the tour leaderboard pages, which contain nearly 60 sortable stats for the top 50 players on each circuit. Many of those stats aren’t available anywhere else, including things like average opponent ranking and time per match. It’s also possible to filter the matches for each calculation to determine things like the best hold percentages on clay.

Last week I introduced three new pages that extend the same concept:

Here’s just one example of what’s possible, the best WTA players outside the top 50 by ace percentage:

These are a great way to identify standout skills of lesser-known players. All of the leaderboards update every Monday.

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What Is Ben Shelton’s Ceiling?

Also today: First serve stats, and new Tennis Abstract reports.

Ben Shelton. Credit: 350z33

Ben Shelton is one of the rising stars of men’s tennis, the most exciting young player this side of Carlos Alcaraz. He possesses a monster serve, he’s not afraid to unleash old-school tactics, and he wears his heart on his sleeve. It’s impossible to root against this guy.

Shelton is also, by the standards of the game’s elite, not a very good returner.

Any discussion of his potential has to come to terms with this most obvious limitation. His rocket of a lefty serve will never hold him back; indeed, it’s already earned him places in the US Open semi-finals and the Australian Open quarters. You don’t have to do much dreaming to see him going even further and winning a major outright. What’s tougher to forecast is the sort of sustained performance that would take him to the top of the rankings.

Last year, Shelton won 32.6% of his return points at tour level. Average among the top 50 was 37.1%, and the top four players on the circuit (and Alex de Minaur) all topped 40%. Of the top 50, only Christopher Eubanks, at 30.9%, came in below Shelton.

There’s plenty of time for Ben to improve, and I’ll get to that in a moment. But first, let me show you the list of the year-end top-ten players with the lowest percentage of return points won (RPW%) since 1991, when the ATP began to keep these stats:

Player              Season  Rank   RPW%  
John Isner            2018    10  29.4%  
Kevin Anderson        2018     6  33.7%  
Milos Raonic          2014     8  33.8%  
Andy Roddick          2007     6  34.0%  
Hubert Hurkacz        2023     9  34.3%  
Greg Rusedski         1997     6  34.5%  
Matteo Berrettini     2019     8  34.6%  
Ivan Ljubicic         2005     9  34.6%  
Hubert Hurkacz        2022    10  34.7%  
Greg Rusedski         1998     9  34.7%  
Stefanos Tsitsipas    2023     6  34.7%  
Mark Philippoussis    2003     9  34.8%  
Andy Roddick          2010     8  34.9%  
Pete Sampras          1996     1  35.3%  
Jo Wilfried Tsonga    2009    10  35.3%  
Goran Ivanisevic      1995    10  35.4%  
Andy Roddick          2009     7  35.5%  
Pete Sampras          2000     3  35.5%  
Pete Sampras          2001    10  35.6%  
Andy Roddick          2008     8  35.6%

In 33 years, out of 330 top-ten finishes, only one man has reached the threshold with a RPW% lower than Shelton’s last year. And it’s someone you can’t exactly pattern a career after: If you look up “outlier” in the dictionary, you find John Isner’s face staring back at you.

Even more striking to me is that no one has finished in the top five with a RPW% below 35%. Then comes another outlier, Pete Sampras and his 1996 campaign. If your goal is to finish a season at number one, you’ll usually need a strong return. Sampras and Andy Roddick are the only two men who have topped the rankings with a RPW% below 38%. Otherwise, you’ve got to ask yourself one question: Are you Pete Sampras?

Here are the lowest RPW% numbers for top-three finishers since 1991:

Player           Season  Rank   RPW%  
Pete Sampras       1996     1  35.3%  
Pete Sampras       2000     3  35.5%  
Andy Roddick       2005     3  36.0%  
Milos Raonic       2016     3  36.1%  
Andy Roddick       2003     1  36.4%  
Casper Ruud        2022     3  36.9%  
Pete Sampras       1999     3  37.3%  
Andy Roddick       2004     2  37.5%  
Boris Becker       1994     3  37.6%  
Michael Stich      1993     2  37.9%  
Pete Sampras       1998     1  38.0%  
Marat Safin        2000     2  38.1%  
Grigor Dimitrov    2017     3  38.2%  
Patrick Rafter     1997     2  38.2%  
Roger Federer      2009     1  38.3%

(Did you expect to see Casper Ruud on this list? I did not.)

Shelton’s serve means that he could reach the top without the return-game success of Alcaraz or Novak Djokovic. But if he wants to move beyond the fringes of the top ten, this second table shows the range he needs to aim for. Setting aside the hot-and-cold tactics of Pistol Pete (we’ll come back to that, too), we can simplify things and say that a would-be world-beater needs to get his RPW% up around 36% or 37%.

How much can a return improve?

Bettering your core stats is possible, but not easy. Another lefty, Feliciano Lopez, offers a cautionary tale. In his age-20 season, he won 31.7% of return points, not far below Shelton’s mark. Here’s how his career developed:

Lopez didn’t top 34% for more than a decade, and he only reached 35% when he was 34 years old. In seven of his ten seasons between the ages of 21 and 30, his return was no more than 1.5 percentage points better than that first season.

Here’s another one. Milos Raonic won 33.5% of his return points as a 20-year-old. He’s a better comp for Shelton, because Raonic’s serve was similarly effective as well. This graph shows how Raonic’s return evolved:

He barely improved on that 33.5% mark until 2016, when he peaked at number three in the ATP rankings, and he couldn’t sustain it. His career RPW% went into the books at 33.9%.

Many of you, I’m sure, are ready to object: Lopez was never the pure athlete that Shelton is! Raonic certainly wasn’t, and he played through one injury after another. Fair enough–if there are natural gifts that make it more likely that a player develops a tour-average return game after arriving on tour, Ben probably has them. Tough to argue with that.

Still, the numbers are brutal. There have been 99 players who racked up 20 or more tour-level matches in their age-20 season since 1991. 22 of them never improved–they never won return points at a higher rate than they did when they were 20. Of the lucky ones who managed to do better at some point in their careers, their peak was, on average, 1.7 percentage points higher than their age 20 number. For Shelton, that’s a peak RPW% of 34.3%, well below the targets established above.

Of that group of 99 20-year-olds, one out of ten improved (eventually) by at least ten percent–not percentage points–a gain that would move Shelton up to 35.9%, essentially the border of where he needs to be for a top-three finish. Let’s not understate the difficulty of the task. Players who reach tour level by age 20 are extremely promising, almost without exception, and Ben needs to put himself in the top tenth of that group.

It’s not obvious why boosting your return-game results is so difficult, or so rare. (It’s harder than improving serve stats, but that’s a topic for another day.) One factor is that as you climb the rankings, you face tougher opponents, so even if your game gets better, your stats appear to stagnate. The median rank of Shelton’s opponents last year was 54.5. The same number for Andrey Rublev is 40, and Daniil Medvedev’s was 27.

Another reason is that returning is a young man’s game. The skills that contribute to the service return–vision, reaction time, quickness, speed–peak early. I have no doubt that Lopez, Raonic, and just about everybody else on tour worked hard to get more out of their return over the years, but many of their gains simply cancelled out the losses they suffered from the aging process.

Beyond RPW%

Sampras was famous for tanking some return games, then going all-out late in the set. The energy-saving strategy was time-tested, going back another half-century to the “Big Game” theories of Jack Kramer and his mentor Cliff Roche. If you hold your serve (almost) every time you toe the line, you only need to break once–or win the tiebreak. Why waste the effort on every return point?

Shelton doesn’t go quite that far; he rarely looks apathetic on return. But he clearly gets energized when an opportunity presents itself, or when he decides it’s time to create one. If a player can consistently play better in big moments, his RPW% won’t tell the whole story. Nick Krygios did this on break points, though it wasn’t enough to get him into the top ten.

There’s some evidence that Shelton does as well. If he always played the same way–the level that earned him 32.6% of his return points–a simple model would predict that he would break serve 13.3% of the time. Instead, he broke 16% of the time, a rate that the model would have predicted for a returner winning 34.4% of points. Still not top-three territory, but getting closer.

Isner often overcame his return woes by securing more tiebreaks than his first-twelve-game performance would have suggested. He won more than 60% of his career breakers, coming close to a 70% mark in two separate seasons. Shelton might be using similar tactics, but he isn’t yet getting the same sort of results: He went a modest 18-16 in tiebreaks last season.

What about break points? This is one area where Sampras noticeably stepped up his game. From 1991 to 2000, he won 44 more break points than expected, based on his return-point stats on non-break points. It’s not a huge advantage–about one extra break of serve every 16 matches–but most players break even. This is one way in which Pete’s RPW% understated his effectiveness on return.

Here, Shelton really shines. My model suggests that he “should” have won break points at a 35.0% clip last year, since on average, players win break points more frequently than other return points. (Break points arise more often against weaker servers.) Incredibly, Ben won more than 41% of his break point chances. Instead of 96 breaks of serve, he earned 114. Since 1991, only a few dozen players have ever outperformed break point expectations by such a wide margin for a full season. Sampras never did, though he once got close.

If Shelton can sustain that level of break-point play, we might as well make room for him in the Hall of Fame right now. A modest improvement in RPW%, combined with reliably clutch performance in the big moments, would move him into the Sampras/Roddick range, where big servers can break serve just enough to catapult to the top of the rankings.

But… it’s a big if. Sampras averaged just four or five extra breaks per season, and he’s one of the all-time greats. In 2003, James Blake also exceeded break-point expectations by a margin of 18. The next year his score was negative 5. Across 2,600 pairs of player-seasons, there’s virtually no correlation between break point performance one year and the next. Shelton may defy the odds, just as Isner rewrote the book on tiebreak performance. But the smart money says that he won’t be so lucky this year.

Where does this leave us? If we’re optimistic about Shelton’s athleticism, commitment, and coaching team, there’s reason to expect that he’ll eventually win more return points–though probably not enough to reach the 36% threshold that usually marks off the top three. If he proves able to execute Kramer/Sampras/Kyrgios tactics under pressure, that might be enough to make up the difference. If he can do that, and he can remain as fearsome a server as he already appears to be, we might have a multi-slam winner, a top-three, maybe even number one player on our hands. The ceiling is high, but the ladder is steep.

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First serve dominance

James Fawcette asks:

[At the United Cup] de Minaur lost only 1 point behind his first serve vs Djokovic, 33 of 34. Has anyone ever won every first serve point vs the then world number one in a completed match?

No!

Going back to 1991, when the ATP started keeping these stats, no one else lost only one, either. Here are the 18 matches in which a player lost three or fewer first-serve points against the world number one. In seven of the matches (noted with asterisks), all that big serving was for naught, and the favorite won anyway.

Tournament         Rd   Winner      Loser       Lost     
2024 United Cup    QF   de Minaur   Djokovic       1     
1992 Tour Finals   RR   Ivanisevic  Courier        2     
1993 Osaka         QF   Courier     Raoux          2  *  
1993 Tour Finals   RR   Sampras     Bruguera       2  *  
1996 Dusseldorf    RR   Kafelnikov  Sampras        2     
2000 Miami         SF   Kuerten     Agassi         2     
2002 Hamburg       QF   Safin       Hewitt         2     
2008 Indian Wells  SF   Fish        Federer        2     
2011 Tour Finals   RR   Ferrer      Djokovic       2     
1992 Paris         QF   Becker      Courier        3     
1992 Brussels      R16  Courier     Leconte        3  *  
1996 Tour Finals   SF   Sampras     Ivanisevic     3  *  
2000 Scottsdale    R16  Clavet      Agassi         3     
2002 Rome          R32  Moya        Hewitt         3     
2008 Halle         SF   Federer     Kiefer         3  *  
2008 Olympics      R64  Federer     Tursunov       3  *  
2010 Tour Finals   F    Federer     Nadal          3     
2018 Canada        R32  Nadal       Paire          3  *

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New toys

Yesterday I added two new features to Tennis Abstract. First, there’s a list of today’s birthdays:

Second, there’s a “Bakery Report” (one each for men and women) with comprehensive stats on 6-0 and 6-1 sets won and lost:

The birthday list will update daily, and the bakery report will refresh every Monday, expect in the middle of grand slams.

Enjoy!

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Do Players Like Daniil Medvedev Eventually Start Winning on Clay?

Daniil Medvedev is within a whisker of the ATP number two ranking, and he has twice reached a grand slam final. He has a big serve, but he’s more than a serve-bot, and his resourceful, varied baseline game suggests he has the tools to excel on all surfaces.

Yet out of 28 career tour-level matches on clay, he’s won 10. Ten wins is an awfully meager haul for a 25-year-old with his sights set on the sport’s top honors.

I put together a list of about 140 ATP top-tenners–that’s basically all of them, with the exception of those whose careers were well underway at the start of the Open Era. For each one, I tallied up their clay court winning percentage in their first 28 matches (or 29 or 30, if the 28th came in the middle of an event), their hard-court results up to the same point in their career, and their eventual clay court results.

When Medvedev played his most recent match on dirt last September, it dropped his clay winning percentage to 35.7%, compared to a hard court record of 116-51, or 69.5%. Few top ATPers have begun their careers so ineffective on clay or so deadly on hard.

In fact, only 5 of the 140 players were worse in their first 28 clay matches. It’s a motley bunch, ranging from Joachim Johansson (who only played 17 matches on the surface in his career) to Kevin Curren (who only got there at age 34) to Diego Schwartzman, who is best on clay, but was overmatched early in his career. The guys tied with Medvedev are an equally mixed crowd, including those who preferred to skip the clay–Tim Henman, Paradorn Srichaphan–and those who took some time to get their footing at tour level, such as Nicolas Almagro and Robin Soderling.

Unlike Daniil Medvedev

This sampling of names suggests that the question I started with is difficult to define. On paper, Henman was “like” Medvedev. By the time he finished his 28th clay match, he had already played 152 times at tour level on hard courts, winning two thirds of them. But their playing styles are so different that the statistical similarities could be misleading.

Let’s narrow the list of comparable players to those who meet the following criteria:

  • lost more than half of their first 28 clay matches
  • had played at least 75 hard-court matches by the time they played their 28th on clay (in other words, they weren’t slow-starting dirtballers like Schwartzman or Almagro)
  • played at least 40 more clay-court matches in their careers (to exclude the blatant clay-avoiders like Curren and Srichaphan)

The following table shows the remaining 14 players, plus Medvedev. I’ve included the age when they played their 28th clay match, and their winning percentages on clay and hard up to that point. The final three columns show how things proceeded from there–after the tournament when they played they 28th clay match (“Future”), you can see how many clay matches they played, what percentage they won, and how many titles they took home:

Player        Age  Clay%  Hard%  Future: M   W%  Titles  
T Johansson  24.1    29%    56%         79  38%       0  
Soderling    21.7    34%    53%        109  70%       3  
Henman       24.7    34%    66%         90  59%       0  
Medvedev     24.6    36%    69%                          
Enqvist      22.1    39%    67%         93  51%       1  
Federer      19.8    41%    62%        266  80%      11  
Rafter       24.4    41%    60%         41  59%       0  
Cilic        20.5    43%    64%        174  65%       2  
Anderson     25.9    43%    60%         80  56%       0  
Isner        25.9    45%    60%        100  57%       1  
Kiefer       21.9    45%    62%         94  45%       0  
Blake        23.4    46%    56%         72  46%       0  
Murray       21.9    48%    76%        125  74%       3  
Bjorkman     25.1    48%    60%         71  31%       0  
Rusedski     24.0    48%    54%         50  30%       0

The results don’t exactly leave Rafael Nadal quaking in his Nikes. 8 of the 14 never won a clay title, and Isner’s 2013 win in Houston barely saves him from making it 9. The combined post-28th-match winning percentage of these guys is just shy of 60%, which isn’t bad, until you consider that without Roger Federer, the rate drops to 55%. The four players that offer some hope for Medvedev–Federer, Soderling, Andy Murray, and Marin Cilic–all played their 28th tour-level match on clay before their 22nd birthday, and even given their relative inexperience, all but Soderling did better in their first 28 than the Russian did.

When we take age into consideration, Henman looks like an even better comp, alongside characters like Pat Rafter and Greg Rusedski. They were more obviously one-dimensional than Medvedev is, but their early-career results offer decent parallels. Medvedev can only hope the similarities end there.

One thing I learned in putting together this list was probably already obvious to most of you–there aren’t a lot of players, now or in the past, who can easily be described as “like” Daniil Medvedev. That makes forecasting even trickier than usual. His height and recent serving prowess almost classes him with Isner and Kevin Anderson, while his game style puts him in a category with … Murray?

There’s another lesson in trying to locate parallels for Medvedev. He’d better hope that he continues to defy easy classification. It’s a bit late to become the next Federer, so if he’s going to become more an occasional threat on dirt, he’ll have a whole lot of historical precedent to overcome.

Economist: Cori Gauff announces herself at Wimbledon

At the Economist’s Game Theory blog, I wrote about Cori Gauff’s historic upset of Venus Williams:

IT IS hard to avoid the impression that the tennis world has witnessed a changing of the guard. On July 1st , the opening day of the 2019 Championships at Wimbledon, Cori Gauff, a 15-year-old American prospect, upset the five-times champion Venus Williams in straight sets. Ms Williams, aged 39, was not the highest-ranked player to fall on the first day of the tournament; that honour belonged to the reigning US Open champion, Naomi Osaka, the second seed. But no first-round winner has garnered more attention than Ms Gauff, whose youth causes her to establish new records every time she steps on court.

Read the whole thing.

Forecasting Future Felix With ATP Aging Patterns

Italian translation at settesei.it

It’s been an exceptional six weeks for Felix Auger-Aliassime. He broke into the top 100 with a runner-up performance on clay in Rio de Janeiro, won two matches each at Sao Paulo and Indian Wells (including an upset of Stefanos Tsitsipas), and raced to a semi-final at the Miami Masters, the youngest player ever to make the final four of that event. Four months away from his 19th birthday, his ranking is up to 33rd in the world, and he has few points to defend until June.

Felix is the youngest man in the top 100, and he’s reaching milestones early enough to draw comparisons with some of the best young players in the sport’s history. Will he follow in the footsteps of past wunderkinds such as Rafael Nadal and Lleyton Hewitt? To answer that question, let’s take a look at typical ATP aging patterns, what they say about when players hit their peaks, and what they can show us about the fate of the best 18 year olds.

The standard curve

Last week, I looked at WTA aging curves and found that women tend to peak around age 23 or 24, an age that has not changed even as the sport has gotten older. I also discovered that there is a surprisingly modest gap–about 70 Elo points–between 18-year-old performance and a woman’s peak level. The men’s results are different.

To calculate the average ATP aging curve, I found over 700 players who were born between 1960 and 1989 and played at least 20 tour-level, tour qualifying, or challenger-level matches in each of five seasons. Overall, peak age was 25, though the difference from age 24 to 27 is only a few Elo points, so small as to be negligible.

As the tour has gotten older, the men’s peak age has also increased. Of the nearly 300 players born between 1980 and 1989, peak age is 26-27, with ages 28 and 29 also within 10 Elo points of the age 26-27 peak. Plenty of players are peaking at older ages, and many of those who aren’t are remaining close to their best levels into their late twenties. The peak age could be even higher still–a few of the players in the 1980-89 cohort turn 30 this year, and could conceivably still improve on their career bests.

The following graph shows the trajectory of the average player (with peak year-end Elo set to 1,850) born in the 1960s and the pattern of the average player born in the 1980s:

It’s a long ascent from the performance level at age 18 to the typical peak, especially for more recent players. There’s even a hefty bit of selection bias that should inflate the level of 18 year olds, since only about 10% of the players in the overall sample qualified for a year-end Elo rating when they were 18. The ones who did were, in general, the best of the bunch.

Felix forward

Through the Miami semi-final, Auger-Aliassime’s Elo rating is 1,848. The average player in the entire dataset who played at least 20 matches in their age-18 season went on to add another 281 Elo points to their rating between the end of their age-18 season and their peak. In the narrower, more recent cohort of 1980-89 births, the players with year-end ratings as 18 year olds improved their Elos by a whopping 369 points before reaching their peaks.

Adding either of those numbers to Felix’s current rating gives us quite the rosy forecast:

Cohort   Current  Increase  Proj. Peak  
1960-89     1848       281        2129  
1980-89     1848       369        2217

There’s a bit of slight of hand in how I’m doing this, since my study uses players’ year-end ratings, and I’m using Felix’s rating in April. However, there’s no natural law that says one artificial 12-month span is better than another, and Felix’s current age of 18.6 is roughly in the middle of the ages of the year-end 18-year-olds with whom I’m comparing him.

An Elo rating of 2,129 would be good enough for fourth place on the current list, behind only the big three. The rating of 2,217 is better than any of the big three can boast at the moment, and would be the fourth-best peak year-end rating among active players, again trailing only the big three. (And Andy Murray, if you consider him active.) Only 15 Open era players have managed year-end Elo peaks above 2,217.

No comparisons

It’s tough to say whether this method, of finding the typical difference between 18-year-old and peak Elo ratings, is adequate to handle the extremes. Some players peak earlier than average, and it stands to reason that the best young talents are more likely to do so. Boris Becker posted a whopping 2,212 Elo rating at the end of his age-18 season, which didn’t leave much room for improvement. He gained another 90 points before the end of his age-19 season, which was his career best.

Becker’s career path is not particularly helpful to our effort to forecast Felix’s, in part because the German was so unique, and also because his experience reflects such a different era. But even among less unique players, there are few useful comparables. No one born since 1987 managed a better age-18 Elo rating than Felix’s 1,848, and only a handful of active or recently-retired players even reached 1,750 by that age.

Lacking the data for a more precise approach, let’s repeat what I did for Bianca Andreescu last week, and see how the nearest 18-year-old comparisons fared. Of the players whose age-18 year-end Elos were closest to Felix’s 1,848, here are the 10 above him and the 10 below him on the list:

Player               BirthYr  18yo Elo  Incr  Peak Elo  
Stefan Edberg           1966      1916   350      2266  
John Mcenroe            1959      1912   496      2408  
Guillermo Coria         1982      1909   145      2055  
Pat Cash                1965      1907   151      2058  
G. Perez Roldan         1969      1884    41      1925  
Andy Murray             1987      1878   465      2343  
Roger Federer           1981      1871   487      2359  
Thomas Enqvist          1974      1865   216      2081  
Rafael Nadal            1986      1862   452      2314  
Jim Courier             1970      1849   283      2132  
…                                                       
Jimmy Brown             1965      1834     0      1834  
Andy Roddick            1982      1815   291      2106  
Aaron Krickstein        1967      1812   246      2058  
Yannick Noah            1960      1812   299      2112  
Fabrice Santoro         1972      1805    85      1890  
Andreas Vinciguerra     1981      1803    16      1819  
Novak Djokovic          1987      1792   645      2436  
Sergi Bruguera          1971      1790   265      2055  
Thomas Muster           1967      1788   329      2117  
Dominik Hrbaty          1978      1779   133      1913

The average increase among this group is 270 Elo points, close to the overall average for players who qualified for a year-end Elo rating at age 18. The youngest members of this list are encouraging: the big four, Andy Roddick, and Andreas Vinciguerra. Most promising youngsters would happily take a two-in-three shot at having a career at the level of the big four.

Perhaps the best comparison for Felix is a player who didn’t quite make that list, Alexander Zverev. The 21-year-old German posted a year-end Elo of 1,768 as an 18 year old, and already boosted that number by more than 300 points at the end of his 2018 campaign. Zverev is only an approximate comparison, he’s just a single data point, and we don’t know where he’ll end up, but his experience is a decade more recent than those of Novak Djokovic, Murray, and Nadal.

Forecasting the career performance of young tennis players is an inexact science, at best. Potential outcomes for Auger-Aliassime range from teenage flameout to double-digit major winner. Based on the limited information he’s given us so far, the latter seems within reach. What we know for sure is that he’s playing better tennis than any 18 year old we’ve seen in a decade. If that’s not reason for optimism, I don’t know what is.

Juan Ignacio Londero’s First Five ATP Match Wins

Italian translation at settesei.it

Last week’s ATP 250s had their share of surprises, with all three top seeds falling in their first matches. But the biggest shock of all was reserved for Sunday, when 25-year-old Argentine Juan Ignacio Londero capped an unexpected breakthrough week in Cordoba with a title. The hometown wild card pummelled Federico Delbonis and then came from behind to defeat Guido Pella a three-set final. Londero was playing just his fourth tour-level event, and his first tour-level win came on Tuesday, a first-round upset of fifth-seed Nicolas Jarry.

There aren’t many players who’ve managed to win a title the same week as their first match win on tour. Going back to 1990, I found only five others who matched Londero’s feat:

Player                Age   Year  Event        
Nicolas Lapentti      19.1  1995  Bogota       
Lleyton Hewitt        16.9  1998  Adelaide     
Juan Ignacio Chela    20.5  2000  Mexico City  
Santiago Ventura      24.4  2004  Casablanca   
Steve Darcis          23.3  2007  Amersfoort   
Juan Ignacio Londero  25.5  2019  Cordoba

It’s a diverse group. Lleyton Hewitt announced his presence with a title as he embarked on a Hall of Fame career, Nicolas Lapentti had great things ahead of him as well, and Juan Ignacio Chela would go on to win six more titles. (Next time a player named Juan Ignacio wins his first ATP match, watch out!) The other two players broke through at older ages and provide better clues as to what we should expect from Londero. Steve Darcis won one more title within a year of his first, and stuck around long enough to crack the top 40 at age 33. Santiago Ventura never played another final, and his career peak ranking was 65, just four spots above Londero’s new level.

A perfect 25

Still, pointing out that Londero is unlikely to develop into a top ten player doesn’t mean we shouldn’t celebrate his accomplishment. I found over 1,000 players who won their first tour-level match since 1990, and only 24% of them managed to win their second match at the same tournament, let alone the title. The average first-time winner claimed a mere 1.3 matches, including their debut win. In addition to the six titlists, only nine reached the final and 43 made it to the semis after recording their first win.

The results for debut winners are even more bleak when we narrow our focus to players in Londero’s age group. Despite the increasing age of the men’s tennis population, if a player hasn’t made an impact on tour before age 25, he is unlikely to do so. 17% of our first-time winners were 25 or older, and Londero is the only one of them to reach the final in his breakthrough event. These 185 players combined for only 53 wins after their first-round milestones, and four of those wins were recorded by Londero last week.

Pessimistic as this sounds, there are a few encouraging precedents for the Argentine to follow. Paolo Lorenzi won his first tour-level match about one month younger than Londero’s current age. It took Lorenzi nearly another decade to hoist his first ATP trophy, and he’s still hovering just ouside the top 100 at age 37. Tennys Sandgren (who, coincidentally, lost to Lorenzi in New York last night), didn’t win a tour-level match until he was 26. Six months later he was in the quarter-finals of the Australian Open. The most extreme late bloomer is Victor Estrella, who was almost 33 years old at the time of his first ATP match win, which he followed with a tour-level title 18 months later.

Of course, Lorenzi is one of a kind, and the unexpected feats achieved by Sandgren and Estrella have minimal predictive value. Beyond the thrill of winning his hometown tournament, the most important implication of the title for Londero is that it launches his ranking into the top 70. He gets a place in the Roland Garros main draw, and in the next twelve months, he’ll have a number of other opportunities to play tour-level events. He deserves it: My Elo rankings suggest he is not only a top-70 player overall, but he is just outside the top 40 on clay courts. Londero’s title truly came out of nowhere, but there’s no reason to be suprised the next time he posts an excellent result on clay.

Danielle Collins and Surprise Major Semi-finalists

Italian translation at settesei.it

With a three-set win today over Anastasia Pavlyuchenkova, Danielle Collins became the first woman into the 2019 Australian Open semi-finals. She was already the biggest surprise of the eight quarter-finalists. A week ago, most pundits (myself included) would’ve picked dozens of players more likely to find themselves in the final four.

Collins, a 25-year-old American, has doubled her grand slam match experience at a single tournament. She first made a name for herself as a stellar collegiate player, winning national titles in 2014 and 2016, which earned her wild cards into her first two majors. While she gave Simona Halep a scare by taking a set in their 2014 US Open encounter, no wins resulted from either of the wild cards. After her run to the Miami semi-finals last year, she earned her way into three more slams, but she drew seeds at all three and had to settle for first-round loser’s checks. All told, Collins’s experience at majors amounted to five main draws, five first-round losses, and a couple of wins in qualifying.

There’s simply no precedent for what she has done in Melbourne. She opened by narrowly upsetting 14th seed Julia Goerges, then won six sets in a row to knock out Sachia Vickery, 19th seed Caroline Garcia, and 2nd seed Angelique Kerber, needing barely one hour per match. Today’s contest took a bit longer, but the end result was the same: a 2-6 7-5 6-1 victory over Pavlyuchenkova, who was playing in her fifth major quarter-final.

A berth in a major semi-final with no previous grand slam match wins: that’s something worth a database query. Since 1980, only three other women have done the same: Monica Seles at the 1989 French Open, Jennifer Capriati at the 1990 French, and Alexandra Stevenson in 1999 at Wimbledon. Collins doesn’t exactly fit in with that trio: Seles and Capriati were playing their first majors, and neither had reached their 16th birthdays. Stevenson was 18 years old, playing only her third slam main draw. The closest comp for Collins is found in the men’s game, where 25-year-old Marco Cecchinato reached the semis at Roland Garros last year despite recording no wins in his previous attempts at majors.

Reaching the final four in one’s sixth slam isn’t as rare. 12 different women have done so, including Seles, Capriati, and Stevenson, along with Venus Williams and Eugenie Bouchard. But again, Collins’s time at the University of Virginia sets her apart from this group: all but one were teenagers, and the only other exception, Clarisa Fernandez, was 20 years old when she reached the 2002 Roland Garros semi-final. The least experienced 25-year-old semi-finalist was Fabiola Zuluaga, who made it to the 2004 Australian Open semis in her 17th major, with 22 match wins in her first 16 tries.

History offers few precedents for Collins. While male collegiates such as Kevin Anderson and John Isner have established themselves in the top ten and gone deep at majors, the women’s game has always skewed younger. Yes, the days of 15-year-old sensations like Capriati and Seles are behind us, but the most recent major title went to 20-year-old Naomi Osaka, and the same year that Collins won her first national title for Virginia, Bouchard–who is two months younger than the American–reached the Wimbledon final. The greatest success story in women’s collegiate tennis belongs to Lisa Raymond, who is best known for her exploits on the doubles court.

Perhaps Collins’s success will change that, much as Anderson–whose first major semi-final came at age 31, in his 34th slam–has shown that college can fit in the plans of a would-be ATP star. With 20% of the WTA top 100 in their thirties, there’s more for a late starter to look forward to than ever before. It’s unreasonable to expect that Collins will be a regular feature at the tail end of grand slams, but it’s possible she’ll outdo Raymond, who peaked at 15th in the singles rankings. Next time we see her in the second week of a major, we won’t be so surprised.