Category: Prospects

The Pending Breakthroughs of 2025

Eva Lys, probably a top-100 player in 2025. Credit: Nuta Lucian

Every year, Challenger maven Damian Kust lists the players he thinks are likely to join the ATP top 100 in the coming year. He did a typically good job last year, picking 14 of the 20 players who reached the threshold in 2024. We can forgive him for missing Jacob Fearnley, who rose from 646th to the top 90 in less than twelve months.

I’ve yet to meet a forecast that I didn’t want to mathematically model, and this is no exception. An algorithm probably isn’t going to do better than Damian does, as it will miss all kinds of details accumulated by a full-time tour watcher. But the exercise will give us a better idea of what factors make it more or less likely that a player joins the top-100 club.

Let’s get straight to the forecast:

Rank  Kust  Player               Rank  Elo Rk   Age  p(100)  
1     3     Joao Fonseca          145      45  18.4   96.5%  
2     4     Learner Tien          122      74  19.1   92.4%  
3     1     Hamad Medjedovic      114      91  21.5   89.1%  
4     5     Nishesh Basavareddy   138      84  19.7   84.2%  
5     9     Raphael Collignon     121      97  23.0   82.5%  
6     8     Martin Landaluce      151      99  19.0   82.1%  
7     6     Jerome Kym            134     111  21.9   79.6%  
8           Leandro Riedi         135     108  22.9   71.9%  
9     15    Jaime Faria           123     146  21.4   69.0%  
10    7     Jesper de Jong        112     117  24.6   66.8%  
11    12    Tristan Boyer         133     116  23.7   64.0%  
12    2     Francesco Passaro     108     147  24.0   60.9%  
13          Harold Mayot          116     154  22.9   57.6%  
14    10    Alexander Blockx      203     102  19.7   56.8%  
15    16    Valentin Vacherot     140     110  26.1   55.2%  
16    11    N Moreno de Alboran   110     132  27.5   52.5%  
17          Lukas Klein           136     126  26.8   47.0%  
18    19    Elmer Moeller         160     160  21.5   37.4%  
19    18    Duje Ajdukovic        142     171  23.9   36.6%  
20          Terence Atmane        158     174  23.0   35.5%  
21          R A Burruchaga        156     177  22.9   28.1%  
22          Matteo Gigante        141     203  23.0   26.8%  
23    13    Vit Kopriva           130     150  27.5   26.3%  
24          Gustavo Heide         172     190  22.8   24.3%  
25          Coleman Wong          170     238  20.6   24.3%  
            …                                                
35    14    Mark Lajal            229     187  21.6   13.4%  
            …                                                
41    17    Dino Prizmic          292     167  19.4   10.6%  
42    20    James Trotter         193     175  25.4   10.4%

The table shows the 25 men who are most likely to make their top-100 debut this year, plus a few more from Damian’s list. I’ve included Damian’s rankings*, as well as each player’s year-end ATP ranking, year-end ranking on my Elo list, and their current age. The final column, “p(100),” is their probability of reaching the ranking milestone sometime in 2025.

* Damian points out that his numbering wasn’t intended as an explicit ranking, though he did end up picking the more obvious players first, with the long shots at the end.

The three columns between the players and their probabilities are the main components of the logistic-regression model. Age, unsurprisingly, is key. The younger the player, the more likely he’ll improve. Plus, the youngest men may have played limited schedules, causing their official rankings to underestimate their ability levels.

It’s a bit unusual to include both ATP rank and Elo rank, since they are simply different interpretations of the same underlying match results. In this case, though, it makes sense. Elo is better at predicting a player’s performance tomorrow, and it outperforms the official list as a way of predicting rankings a year from now. However, we’re trying to forecast ranking breakthroughs less than a year from now. If Fonseca has a good month Down Under, he’ll crack the top 100 in large part thanks to his eleven months’ worth of ranking points from 2024. In this model, then, the ATP ranking tells us how close a player is to the point total he needs. Elo tells us more about how likely he is pile up the remaining wins.

A player’s existing stock of points turns out to be somewhat more important than his underlying skill level. The model weights ATP ranking about half-again as heavily as Elo rank.

There are innumerable other variables we could include. I tested a lot of them. The only other input I kept was height. Height is only a minor influence on top-100 breakthroughs, but it’s definitely better to be taller. De Jong, for instance, is five feet, eleven inches tall. He ranks eighth on the 2025 list when height is omitted, and falls to tenth when height is included.

This tallies with the Challenger-to-tour conversion stats I worked out for my recent post about Learner Tien. Both short players and left-handers have a harder time making the jump than their taller, right-handed peers. Those conversions don’t address quite the same thing, since it’s possible to crack the top 100 with little to no success at tour level–it just means winning lots of Challengers. For that reason, left-handedness is probably an advantage for players aiming to jump from, say, 122nd to the top 100, as Tien is now. The relationship between left-handedness and breakthrough likelihood was less clear-cut than height, though, so I left it out.

J-wow

Enough mechanics–back to the forecasts. Fonseca’s 96.5% probability might strike you as crazily high or outrageously conservative. It’s certainly confident, but then again the Brazilian is a special player. Barring injury–and immediate injury, at that–a breakthrough seems likely to happen soon.

Whether high or low, the Fonseca forecast is unusual. Like his forehand, it puts him in classy company. Going back to 2000, here are the players about whom the model would have been most optimistic:

Year  Player                 Rank  Elo    Age  p(100)  Y+1  
2021  Holger Rune             103    50  18.7   98.7%   10  
2020  Sebastian Korda         118    48  20.5   97.9%   38  
2024  Joao Fonseca            145    45  18.4   96.5%       
2010  Grigor Dimitrov         106    75  19.6   96.3%   52  
2020  Carlos Alcaraz          141    51  17.7   96.1%   32  
2018  Felix Auger Aliassime   108    89  18.4   95.8%   17  
2023  Hamad Medjedovic        113    66  20.5   95.4%  105  
2000  Andy Roddick            156    52  18.3   94.5%   14  
2020  Lorenzo Musetti         128    68  18.8   94.0%   57  
2019  Emil Ruusuvuori         123    64  20.7   94.0%   84

It’s not so remarkable that eight of the nine other players on the list succeeded in reaching the top 100. The forecast would have expected (at least) that. But even including Medjedovic’s disappointing finish to 2024, the average ranking of these nine guys at the end of the following season (“Y+1”) is 45. Three broke into the top 20. And Fonseca’s forecast places him ahead of most of them.

Medjedovic’s near-miss was due in part to illness. It’s worth remembering that this model only predicts a single year; the young Serbian is still set up for a nice career. (Including, probably, a top-100 debut in 2025.) The model would have given Francisco Cerundolo a 90% chance of breaking through in 2021. He didn’t make it, yet he reached the top 20 a couple of years later. Fernando Gonzalez failed to convert an 80% chance in 2001, but after a few more years, he made the top ten.

Using a simple model–instead of the expert opinion of someone like Damian–exposes us to another type of error. The model is optimistic about the 2025 chances of 22-year-old Leandro Riedi, who possesses both official and Elo ranks on the cusp of the top 100. On paper, he’s a great pick. But he had knee surgery in September. Instead of defending points from two Challenger titles in January, he’s continuing to recover. He may ultimately surpass many of the other guys on the list, but even just regaining his pre-injury form this year is a big ask.

Waiting for Eva

Let’s run the same exercise for the women’s game. Unfortunately I don’t have enough height data, so we can’t use that. The resulting model is less predictive than the men’s forecast (even apart from the lack of player heights), but with year-end WTA rank, Elo rank, and age, it’s almost as good.

Patrick Ding took up the task of a Kust-style list for women. It’s unordered, so I’ve added a “Y” in the “PD” column next to his picks:

Rank  PD  Player                Rank  Elo   Age  p(100)  
1     Y   Eva Lys                131   43  23.0   80.1%  
2     Y   Anca Todoni            118  100  20.2   74.9%  
3     Y   Maya Joint             116  173  18.7   65.8%  
4         Aoi Ito                126  109  20.6   65.4%  
5     Y   Marina Stakusic        125  131  20.1   62.3%  
6     Y   Polina Kudermetova     107  159  21.6   61.8%  
7     Y   Alina Korneeva         177   80  17.5   61.8%  
8     Y   Robin Montgomery       117  155  20.3   61.1%  
9     Y   Sara Bejlek            161   88  18.9   59.9%  
10        M Sawangkaew           130   94  22.5   58.8%  
11        Anastasia Zakharova    112  145  23.0   54.1%  
12    Y   Sijia Wei              134  135  21.1   49.9%  
13    Y   Celine Naef            153  124  19.5   48.8%  
14    Y   Antonia Ruzic          143  105  21.9   48.7%  
15        Maja Chwalinska        128  119  23.2   47.7%  
16    Y   Sara Saito             150  182  18.2   43.1%  
17        Alexandra Eala         148  162  19.6   41.6%  
18    Y   Darja Semenistaja      119  192  22.3   41.5%  
19    Y   Dominika Salkova       151  150  20.5   38.1%  
20        Talia Gibson           140  185  20.5   37.2%  
21        V Jimenez Kasintseva   156  170  19.4   36.3%  
22    Y   Ella Seidel            141  205  19.9   36.2%  
23    Y   Iva Jovic              189  157  17.1   33.8%  
24        Daria Snigur           139  161  22.8   32.0%  
25        Francesca Jones        152  106  24.3   31.5%  
26    Y   Solana Sierra          163  156  20.5   30.2%  
27    Y   Ena Shibahara          137  103  26.9   29.1%  
28        Lois Boisson           204   95  21.6   23.9%  
29        Elsa Jacquemot         159  191  21.7   21.8%  
30    Y   Taylah Preston         170  246  19.2   20.0%  
31    Y   Tereza Valentova       240  127  17.9   19.6%  
32        Elena Pridankina       186  201  19.3   18.9%  
33        Lola Radivojevic       185  186  20.0   18.9%  
34    Y   Oksana Selekhmeteva    176  176  22.0   16.8%  
35        Barbora Palicova       180  202  20.8   16.2%

This isn’t quite a fair fight with Patrick, because he made his picks in early October. Two of his choices (Suzan Lamens and Zeynep Sonmez) have already cleared the top-100 hurdle. He would presumably consider Ito more carefully now, since she reached a tour-level semi-final two weeks after he made his list. I should also note that Patrick picked two prodigies outside the top 300: Renata Jamrichova and Mia Ristic. My model didn’t consider players ranked that low. I had to draw the line somewhere, and Fearnley aside, single-year ranking leaps of that magnitude are quite rare.

The mechanics of the algorithm are pretty much the same as the men’s version. The women’s list looks a bit more chaotic, pitting players with strong Elo positions (such as Lys and Korneeva) against others who are close to 100 without the results that Elo would like to see (Joint, Kudermetova, etc).

Eva Lys is fascinating because this is her third straight year near the top of the list. She finished 2022 ranked 127th, standing 71st on the Elo table. Just short of her 21st birthday, that was good for a 76% chance of reaching the top 100 the following year–second on the list to Diana Shnaider. She rose as high as 112, but no further.

A year older, Lys was fourth on the 2023 list. Her WTA ranking of 136 and her nearly-unchanged Elo position of 72 worked out to a 67% chance of a 2024 breakthrough. Only three players–Brenda Fruhvirtova, Erika Andreeva, and Sara Bejlek–scored higher. She came within one victory of the milestone in September but finds herself back on the list for 2024.

Even beyond Lys’s 80% chance of finally making it in 2025, history is encouraging. I went back 25 years for this study, and only two other players would have been given a 50% or better chance of reaching the top 100 for three consecutive years. Stephanie Dubois was on the cusp from 2005 to 2007, finishing the third year ranked 106th. She finally made it in 2008. More recently, Wang Xiyu was within range from 2019-21. (Covid-19 cancellations and travel challenges didn’t help.) She not only cleared the hurdle in 2022, she did it with style, climbing to #50 by the end of that season.

The same precedents bode well for Bejlek, who had a 52% chance of breaking through in 2023, a 77% chance last year, and a 60% probability for 2025.

Mark your calendars

In twelve months, we can check back and see how the model fared against Damian and Patrick. The algorithm has the benefit of precision, and it is less likely to get overexcited about as-yet-unfulfilled potential. The flip side is that it doesn’t consider the innumerable quirks that might bear on the chances of a particular player.

For now, I’m betting on the humans.

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Joao Fonseca and Damage Down the Line

Joao Fonseca doing what he does best

Joao Fonseca made easy work of last week’s Next Gen Finals. He went undefeated against the world’s best under-21s, dropping just one set in best-of-five semi-finals and finals. The youngest player in the field, he joins Jannik Sinner and Carlos Alcaraz as 18-year-old champions in the seven-year history of the event.

There’s no secret to Fonseca’s success. He already possesses a devastating forehand, a shot with power that invites comparisons to fellow South Americans Juan Martin del Potro and Fernando Gonzalez. Outrageous as it sounds, Fonseca’s might turn out to be even better. The Brazilian has a more compact stroke, making his forehand more flexible–and perhaps ultimately more reliable–than the long-levered Delpo motion.

In his round-robin match against Jakub Mensik, the TennisTV broadcast flashed a stat meant to indicate one way Fonseca excels:

The TennisTV commentators were flabbergasted by these numbers: They’d never seen anything like it. Hugh, responsible for the screenshot here, got straight to the point. If a player with a forehand like Fonseca’s can consistently send the ball to his opponent’s weaker side, it’s game over.

The easiest direction to hit a groundstroke is back the way it came. That’s how we end up with protracted cross-court rallies. It takes impeccable timing to react to a elite-level cross-court forehand and change direction. (Pros drill that specific sequence, but no amount of practice makes it easy.) Down-the-line shots are doubly difficult because the net is higher as it nears the posts. The timing needs to be near-perfect, and there’s a smaller margin for error.

Here’s another way to get a sense of the dangerous risk level of down-the-line groundstrokes. Novak Djokovic, king of the down-the-line backhand, doesn’t hit that many of them. The inherent limitations of tennis rackets and the dimensions of the court are unforgiving. Fonseca, if he can really hit more than half of his forehands down the line, could defy those limitations.

Fact-check

Normally, I’d give you all sorts of numbers to help anchor Fonseca’s stats. How much does his 56% clip exceed tour average, or compare to someone like Sinner? That’s my goal, but first, we need to get into the weeds a bit.

The Match Charting Project has 14 Fonseca matches in the database, including all five of his NextGen Finals contests. Here’s the breakdown of groundstroke direction for the Mensik match:

This is… not the same as the broadcast graphic. We should expect minor differences, both because the 44/56 stat was shown midway through the match, and because reasonable people can disagree about how to classify shots that don’t obviously belong to a specific category. But that’s not what’s going on here. There’s virtually no way to take these numbers and conclude that Fonseca hit more than half of his forehands down the line.

What’s more, Fonseca’s forehand-direction profile is rather pedestrian. That’s not to say that his forehand is ordinary, just that he aims in the same directions as his peers. Here is Joao’s forehand-direction distribution, based on those 14 charted matches, compared with tour average:

DIRECTION      Fonseca  Average  
Cross-court        40%      39%  
Middle             20%      22%  
Down the line      10%      11%  
Inside-out         26%      24%  
Inside-in           4%       4%

Ho-hum, right? Maybe he hits a few more inside-out forehands instead of going back up the middle. Even there, the two-percentage-point gaps between Fonseca and tour average could be an artifact of the matches we’ve charted. The Brazilian’s forehand does plenty of damage, but as a function of how he hits it, not where.

More weeds, sorry

I should probably let the discrepancy go, but let’s give it another minute. I don’t think the broadcast graphic was wrong, but it’s clearly measuring something different than what I count for the Match Charting Project stats. Maybe there’s some important subset of forehands that Fonseca is unusually likely to hit down the line?

One of the more difficult–and damaging–specific shots is the forehand down the line from the forehand corner. The MCP divides the court into three sectors by width: to the (right-hander’s) forehand corner, down the middle, and to the backhand. Maybe Fonseca particularly likes to change direction when he sees a ball in his own forehand corner?

A bit, but not by much. Here are the direction frequencies for Fonseca’s forehands from his forehand corner, for both the Mensik match and the average of his charted matches, along with the frequencies for his opponents:

             To FH  Middle    DTL  
vs Mensik    58.1%   22.6%  19.4%  
Fonseca Avg  49.0%   23.6%  27.5%  
Opp Avg      45.7%   30.9%  23.4%

Nothing really dramatic here, and he went down the line less often in the Mensik match than his typical opponent does.

What about when Fonseca gets a ball down the middle? We saw in the MCP stats above that he hits a lot of inside-out forehands. That includes shots from the middle to the backhand side of a right-handed opponent. Here is the same group of frequencies for the same sets of matches, this time excluding left-handed opponents because they will naturally make different choices from the middle of the court:

              To FH  Middle    DTL  
vs Mensik     29.7%   25.7%  44.6%  
Fonseca Avg   39.7%   20.0%  40.3%  
(RH) Opp Avg  34.2%   25.4%  40.4%

There’s a few more down-the-line shots in the Mensik match. But over 14 matches, Fonseca differs from his opponents only in hitting fewer balls back up the middle.

Maybe you’ve already worked out the underlying discrepancy. Since the 44/56 split adds up to 100%, there’s no “down the middle” category in the broadcast stats. The graphic splits forehands into two buckets, not three. That’s not how I think about tennis, and I suspect it’s not how you do, either. They would have done better to label the columns “to the forehand” and “to the backhand,” or something along those lines. It’s not unusual at all to hit 56% of one’s forehands to the opponent’s backhand side. But a lot of those “to the backhand” shots are not what anybody would normally call “down the line.”

The Fonseca difference

It’s not about tactics, it’s good old-fashioned power and precision. Fonseca’s forehand isn’t innovative, and it doesn’t need to be. If he hits his shots in more or less the same directions that his peers do, he’s probably doing something right. It means that at age 18, he has already internalized pro tactics. The difference is that he’s hitting those forehands harder, and he’s often landing them closer to the lines, something hinted at by his low rate of down-the-middle forehands.

He already shows up near the top of my Forehand Potency (FHP) leaderboard–though I’ll give you some caveats in a minute:

Rank  Player              FHP/100  
1     Andrey Rublev          14.0  
2     Jan-Lennard Struff     11.6  
3     Joao Fonseca           11.3  
4     Stefanos Tsitsipas     11.0  
5     Carlos Alcaraz         10.8  
6     Rinky Hijikata          9.7  
7     Jannik Sinner           9.4  
8     Casper Ruud             9.2  
9     Juncheng Shang          8.6  
10    Novak Djokovic          8.6

FHP combines forehand winners and errors, along with shots that lead to both opponent errors and winners on the player’s next shot. Given the vagaries of estimating the effect of one shot on others, Fonseca effectively sits in a tie for second place, as good or better than everyone except for Andrey Rublev. Which, I’d say, checks out.

The caveats lie in the dataset. The Brazilian has faced only one top-20 opponent, and that was a possibly-unmotivated #20 Arthur Fils last week. The charting data on which FHP numbers are based includes all the NextGen Finals matches, along with some Challenger-level matches and some early rounds at ATPs. After all, he’s 18 and that’s all he’s played. Point being, an 11.3 FHP/100 (per 100 forehands) against that level of competition probably isn’t is good as Alcaraz’s 10.8 or Sinner’s 9.4, amassed against foes like each other.

But don’t take that adjustment too far. Fonseca scored a 11.0 against Fils in Rio, when he was barely 17 and a half. Facing Botic van de Zandschulp in a Davis Cup tilt, he registered a whopping 16.7 FHP/100. The Dutchman is hardly easy pickings: When Sinner played van de Zandschulp twice early in the season, he managed just 1.2 and 7.1 on the same metric.

Damage (not just) down the line

Fonseca doesn’t hit an unusual number of forehands down the line, but when he does, opponents barely stand a chance. Among the 200-plus players with as many down-the-line forehands in the MCP database as Fonseca has, he ranks sixth in points won when he hits the shot. Admittedly, it’s an odd list:

Rank  Player                   W/FE%   UFE%  inPtsWon%  
1     Juncheng Shang           33.6%  13.1%      66.4%  
2     Nishesh Basavareddy      29.4%  10.3%      65.1%  
3     Luca Van Assche          22.9%  11.0%      62.4%  
4     Hyeon Chung              30.1%  19.9%      61.8%  
5     Bjorn Borg               26.3%   7.3%      61.6%  
6     Joao Fonseca             31.1%  17.6%      61.3%  
7     Rafael Nadal             28.9%  12.8%      61.2%  
8     Camilo Ugo Carabelli     10.3%   9.6%      60.9%  
9     Corentin Moutet          29.4%  15.6%      60.6%  
10    Zhizhen Zhang            22.8%  15.9%      60.3%  
11    Guillermo Garcia Lopez   20.3%   5.9%      60.1%  
12    Roberto Carballes Baena  10.1%   5.8%      59.7%  
13    Carlos Alcaraz           26.7%  14.3%      59.7%  
14    Grigor Dimitrov          23.8%  13.4%      59.3%  
15    Juan Martin del Potro    26.8%  12.7%      59.2%  
                                                        
      Average                  20.1%  15.2%      53.4%

The 2024 Next Gen field is bizarrely well-represented, with Shang, Basavareddy, and Van Assche leading the way. Is this the age of the deadly down-the-line forehand? Some of the same caveats apply here as with the FHP list: The youngsters have played a different sort of opponent than Nadal, Alcaraz, or (!) Borg. The clay-courters on the list also make for awkward comaprisons. For dirtballers, the down-the-line forehand is a way to build points, not end them.

It’s clear that Fonseca loves this play. He ends points in his favor (with a winner or forced error) more than anyone on this list except for Shang.

Here’s the scary thing: A few clay-court matches are severely dragging down the Brazilian’s numbers. On hard courts, he moves up to second on the list, winning 68% of points in which he hits a down-the-line forehand. The shot ends points outright an incredible 48% of the time. Delpo’s numbers, though of course against stronger competition, pale in comparison, at 60% and 39%, respectively.

Some of the difference between Fonseca and the field is that his forehand is great, period. If you’ve got an extra ten miles per hour that the average player doesn’t, that’s going to show up in every direction, not just one. And for the most part, that’s what we see in Joao’s points won when hitting each category of forehand:

FH Pts Won     Fonseca  Tour  
Cross-court        58%   54%  
Middle             52%   46%  
Down the line      59%   53%  
Inside-out         57%   57%  
Inside-in          54%   59%

He’s better than average in all but the rarest of the five forehand directions. Even that isn’t really a negative: On hard courts he does better than tour average with the inside-in forehand.

The eye-catcher on that chart is 52% of points won when hitting a down-the-middle forehand. The typical player is likely to lose a point when hitting that shot. That’s not necessarily because down-the-middle forehands are bad, but because if you need to hit one, the point probably isn’t going your way. Unlike the other categories of forehands, it’s usually a defensive shot.

Of the 220-plus players with as many down-the-middle forehands as Fonseca in the MCP database, only 23 win more than half of those points. The Brazilian ranks fourth by points won when hitting down-the-middle forehands. It’s another oddball list, with Pablo Andujar, Tim Smyczek, Gilles Simon, and Carlos Berlocq rounding out the top five. (Yes, really.) To the extent we can group them together, those four men played a different brand of tennis, winning points with conservative shots as they wore down their opponents.

The more telling stat is that Fonseca actually ends points by clubbing forehands down the middle. The average player hits a winner or induces a forced error with less than 2% of these strokes. Joao comes in at 6.4%, better than anyone else in the dataset:

Rank  Player               W/FE%  inPtsWon%  
1     Joao Fonseca          6.4%      52.8%  
2     Fernando Gonzalez     6.0%      43.2%  
3     Christopher Eubanks   5.7%      38.8%  
4     Thanasi Kokkinakis    5.0%      46.1%  
5     Tomas Machac          4.9%      43.8%  
6     Nicolas Jarry         4.7%      41.7%  
7     Alexei Popyrin        4.4%      41.8%  
8     Sam Querrey           4.3%      41.8%  
9     Max Purcell           4.0%      38.5%  
10    Lorenzo Sonego        3.9%      46.0%  
11    Matteo Arnaldi        3.8%      49.5%  
12    Lucas Pouille         3.4%      42.9%  
13    Jan-Lennard Struff    3.3%      45.6%  
14    Matteo Berrettini     3.3%      42.1%  
15    John McEnroe          3.3%      44.0%  
16    Otto Virtanen         3.2%      35.8%  
17    Boris Becker          3.2%      44.1%  
18    Nick Kyrgios          3.2%      43.2%  
19    Roger Federer         3.2%      47.6%  
20    Carlos Alcaraz        3.2%      50.2%

When you can end points with your forehand twice as often as Federer did, you’re doing something right. The only players even close to the Brazilian’s winner rate end up losing far more points, probably because they need to take many more risks to get that small sliver of positive outcomes.

One more time for the road: Fonseca’s numbers are probably inflated due to his level of competition. In 2025, we’ll see how his forehand holds up against the elites. If we revisit these numbers twelve months from now, he’ll probably come down a notch. But raw power plays at every level. No matter who stands across the net, Fonseca’s forehand is fearsome–in all directions.

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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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Tomas Machac’s Defiant Angles

Tomas Machac at the 2023 US Open. Credit: Hameltion

2024 is quickly turning into the year of Tomas Machac. The 23-year-old Czech reached his first grand slam third round in Australia, straight-setting Frances Tiafoe for a first top-20 win. A quarter-final showing in Marseille and a defeat of Stan Wawrinka at Indian Wells earned him a place in the top 60.

Now, in Miami, he has dispatched top-tenner Andrey Rublev and outlasted Andy Murray for a place in the fourth round. The live rankings place him precariously in the top 50; tomorrow’s match against fellow second-week surprise Matteo Arnaldi give him a chance to make it official. While Jiri Lehecka, a year younger and considerably higher in the rankings, is the poster boy for the resurgence of Czech men’s tennis, Machac is right behind him.

The key to the Machac game is a compact, versatile backhand that seems capable of anything. Inside-out backhands are usually little more than a curiosity, a miracle of timing that many players don’t even bother to try. The Czech hits one in ten of his backhands that way. Against Rublev, he cracked five: one for a winner and two more that forced errors. He won all five.

The tactics that surround Machac’s backhand are a joy to watch. Since he doesn’t serve big, every point threatens to become a rally. But the Czech angles for court position like a much bigger hitter. He approached the net 35 times in yesterday’s Murray match alone. Counting the times he was forced to come forward as well, he played 48 points in the forecourt, winning 38 of them. Combined with a court-widening slice serve, the net play makes Machac just as much of a threat on the doubles court. With Zhang Zhizhen, he reached the semi-finals in Australia and won the title in Marseille. He and girlfriend Katerina Siniakova would make a dangerous mixed duo at the Paris Olympics.

The unknowns that could limit Machac’s ceiling are, well, everything else. His forehand is a bit hitchy and it is nowhere near as effective as his backhand. By my Forehand Potency metric (FHP), he earns barely any points off that wing, ranking among the likes of Adrian Mannarino and Mikael Ymer.

And then there’s the serve. While he is capable of firing bullets–one of his serves in Australia registered at 128 mph (208 kph)–he rarely goes that route. His first serves in Miami have hovered around 110 mph, so he sets up points with slices wide, especially in the deuce court. He manages a respectable ace total thanks to a well-disguised delivery and the surprise that comes from his occasional bombs down the T.

The Machac serve is not a liability, exactly, but it is not the standard first-strike weapon for a prospect in today’s men’s game. Let’s take a closer look.

Lean right

Aside from keeping an eye on the radar gun while watching Machac’s progress in Miami, I don’t have a lot of data to put his serve speed in context. The only available point-by-point serve speed data these days comes from Wimbledon and the US Open, where the Czech has played just two career main-draw matches.

At Wimbledon last year, Machac’s first serves clocked an average of 115 mph (184 kph), faster than about one-third of the field. The Wimbledon gun might have been a little hot, as most players scored better there than in New York, and by a wider margin than you’d expect from more serve-centered tactics. When the Czech played a match at the US Open in 2022, his average first serve speed was 107 mph (171 kph). Four-fifths of the field hit harder; most of the names in his part of the list are clay-courters. Presumably he has gotten stronger since then, so while 115 mph may be an overestimate, 107 mph is probably low.

These numbers confirm that the serve won’t hold him back too much. Some other men in the same neighborhood are Casper Ruud, Tommy Paul, and David Goffin. Neither Carlos Alcaraz nor Novak Djokovic averaged much faster than Machac on the Wimbledon gun last year, and they did just fine. The Czech has only a bit of ground to make up with the rest of his game, and Ruud offers one example that it can be done.

What makes Machac’s serve look so pedestrian is the frequency with which he spins wide serves in the deuce court. Against Murray yesterday, he hit 54% of his deuce-court firsts to the wide corner. Fewer than 40% went down the T, and most of the remainder were also to the forehand side. He was even more extreme in the ad court, spinning 61% of those first serves down the T to the opponent’s forehand.

60/40 sounds rather undramatic, like most tennis stats. But few men favor one direction so strongly, at least until they reach critical situations like break point, when they lean more heavily on their favorite angle. Machac tries to balance it out by aiming for the backhand with his second serves, though by a slightly narrower margin. That does the job: The gap between his first- and second-serve results is about the same as tour average.

In the deuce court, at least, the tactic is working. Against Murray yesterday, Machac won 18 of 22 (82%) when his first serve went wide, though he was nearly as successful down the T. Against Rublev, he won 13 of his 14 wide deuce-court first serves. Understandably, he didn’t hit many deuce-court serves anywhere else. When Murray broke back yesterday to keep the third set alive, it wasn’t the serve itself that let Machac down. Twice at deuce, the Czech missed first serves when he tried to go down the T. His wide second serves drew weak replies on both occasions, but he lost both points with unforced errors.

The dis-ad-vantage

Wide serves in the deuce court are a gamble. You let your opponent take a swing at a forehand–probably his preferred wing–but you pull him out of position. Clearly it can work. Few men rely more heavily on their forehand than Rublev does, yet Machac attacked that side at every opportunity.

Murray was cannier and kept things much closer than Rublev did. But even he was fighting a losing battle. Machac won 80% of total first-serve points in the deuce court yesterday, compared to 69% in the ad court. So far, the Czech’s opponents have been more like Murray than Rublev, but still, the serve-to-the-forehand gamble pays off.

While he likes to aim for the same wing in the ad court as well, Machac doesn’t get the same court-position advantage. Across ten matches logged so far by the Match Charting Project, he has won 78% first-serve points in the deuce court against 71% in the ad court.

The difference lies largely in what Machac can do with his plus-one shot. In the deuce court, he wins about half of first-serve points with his serve or plus-one. In the ad court, that number falls below 40%. 50% is excellent: Djokovic hardly does better than that, and even an imposing server like Ugo Humbert does worse. But 40% is dire. Only clay-courters win so few short first-serve points overall. There’s less room to put away the second shot when you’ve left the returner standing in the middle of the court.

There’s nothing inherently wrong with a split between deuce-court and ad-court results. If asked, most players would probably prefer to win more points in the ad court, since most break points start in that direction. But the effect of winning more break points is mostly cancelled out by earning fewer break chances in the first place. Anyway, Machac doesn’t have any particular problem saving break points. He survived 13 of 15 against Murray. At tour level since this time last year, he has saved 64.5% of break points faced while winning 65.5% of serve points overall. That’s a closer margin that most players can boast.

The deeper we dig, the more we find weaknesses and unusual preferences in Machac’s game. Paired with each one, it seems, is a way in which it could work to his advantage. So far, he has succeeded despite the oddities. His results against Rublev and Tiafoe suggest that stronger competition might not break the spell, though the demands of yesterday’s gutbuster with Murray makes me wonder if brainier competition will raise the bar.

As the men’s game gets ever more powerful, there is less room at the top for playing styles that break the mold. Machac has already hinted that he can counterbalance brute force with the right set of angles, especially if they create opportunities for him to deploy his top-tier backhand. Countryman Radek Stepanek cracked the top ten with his own brand of unorthodox unpredictability. Machac has a different set of quirks, but based on his rapid progress this year, he may be able to do the same.

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Welcome to the Show, Luciano Darderi

Luciano Darderi in 2023. Credit: jmmuguerza

Italian tennis hardly needs any more prospects, but Luciano Darderi has announced himself as yet another young player to watch. The Argentinian-born right-hander turns 22 today, three days after securing his debut ATP title. He came through qualifying in Cordoba, and in just his third appearance in a tour-level main draw, knocked out the 2nd, 4th, and 7th seeds en route to the championship.

Darderi is a supercharged clay courter, comfortable on dirt yet possessing a serve and forehand that will play on faster surfaces. He cracked 25 aces in the Cordoba main draw, plus another 11 in qualifying. On Sunday, fellow qualifier Facundo Bagnis got barely half of Darderi’s first serves back in play. Against Sebastian Baez in the semi-finals, the Italian ended 22 points with a forehand winner or forced error and, as we will see, held his own from the baseline against one of the game’s most stubborn defenders.

Though the magnitude of Darderi’s breakthrough came out of nowhere, he has been inching toward a double-digit ranking for some time. He reached 13 Challenger quarter-finals last year, advancing to three finals and collecting a pair of titles. He finished the year ranked 128th and gained 60 places with the victory in Cordoba, ensuring he’ll have plenty more chances to prove his mettle on tour.

He hasn’t hesitated to take advantage, dropping just three games in beating Mariano Navone in Buenos Aires yesterday. The victory extended the Italian’s winning streak to eight and shows just how fast he is developing, having lost to Navone in a bruising Challenger final just a few months ago.

It won’t always be so smooth for Darderi: The hard-court skew of the top level of the circuit may not prove hospitable to a youngster who has played 84% of his career matches on clay. Even with the right weapons in hand, it will take some time to become more than just a dark horse on the Golden Swing. But that’s all in the future: Darderi’s 22nd birthday is an ideal opportunity to dig into the upsets that lifted him from Challenger warrior to the top 100.

Bullying the little guy

The defining win of the Italian’s week in Cordoba was the semi-final. Baez struggled at the end of 2023, but he is always a tough out on clay, especially coming off a third-set-tiebreak victory in Davis Cup. At just five-feet, seven-inches tall, the Argentinian relies on speed and defense, neutralizing the weapons of larger men. It doesn’t always work–his serve puts him at an immediate disadvantage, and he can become overly aggressive and error-prone to compensate–but he doesn’t give much away.

Despite his size, Baez doesn’t mind going toe-to-toe with an opponent’s best shot. In 19 clay-court matches tracked by the Match Charting Project since the beginning of 2022, Baez’s opponents have hit forehands–excluding service returns–as 61% of their baseline shots, compared to a tour-wide clay-court average of 55%. Thomaz Bellucci found the forehand 72% of the time against the Argentinian; Tallon Griekspoor clocked in at 71%.

Both lost. No matter what the shot, if you find yourself in a rally with Baez, your odds aren’t good. When you hit a forehand after the service return, your chances of winning the point are 45%; with a backhand, your chances are 44%. (Tour averages on clay are 53% and 47%, respectively.) Some individual cases are downright comical. In the 2022 Bastad quarter-finals, Dominic Thiem won just 27% of points when he hit a forehand. When the two men met again in the Kitzbuhel final last year, Thiem relied a bit more on his backhand. Alas, he won only 14% of points when he hit one of those.

Darderi ran around a few backhands to find his bigger weapon, but he generally refused to take the bait. He waited for his spots to attack one of the toughest men on tour to be patient against. This table details the results he got from his forehands and backhands in the semi-final:

                   FH/GS  FH W%  FH Wnr%  FH UFE%  
Darderi vs Baez    55.4%  50.6%    12.2%     8.5%  
Average vs Baez    60.6%  45.2%    10.4%    12.0%  
                                                   
                   BH/GS  BH W%  BH Wnr%  BH UFE%  
Darderi vs Baez    44.6%  48.5%     6.1%     6.8%  
Average vs Baez    39.4%  43.8%     6.3%    10.3%

The Italian hit fewer forehands than the usual Baez opponent, and it won him more points, in part thanks to hitting winners at a higher rate and coughing up fewer unforced errors. His backhand numbers were favorable as well, perhaps in part because he set up for backhands in places where other opponents would go for an inside-out forehand. He was particularly stingy with free points on that wing.

Despite possessing the bigger gun, Darderi let his opponent make the mistakes. Baez obliged, piling up 32 unforced errors, including an uncharacteristic 11% of his backhands. Winning percentages of 50.6% and 48.5% hardly make for good headlines, but coupled with a big serve, they are enough to beat Baez. Few players on tour have been able to manage the same.

Tailored attack

The classic clay-court baseline weapon is the inside-out forehand, a salvo that might not end the point, but will pull the opponent out of position and leave the court open for a finishing blow. Darderi can win matches with that shot, as he did in the final against Bagnis. His left-handed opponent kept sending balls to his backhand corner, and the Italian ran around a lot of them. More than half of Darderi’s forehands in the final were inside-out, and he won the point 78% of the time he hit one. The match wasn’t close.

As we’ve seen, though, manufacturing forehands against Baez is a trap. The Argentinian can blunt the angle and absorb the pace, and meanwhile, his opponent is out of position. When Thiem had his terrible day in Bastad, he hit 62 inside-out forehands, only 16 of them in points that he won. (He typically wins more than half, as does the tour as a whole.) Whether by preparation or intuition, Darderi took those chances much less often, and far less frequently than he would against Bagnis. Just one in six of his forehands were of the inside-out variety, and he won just shy of half those points.

Instead, with Baez accustomed to playing defense on the backhand side, Darderi attacked to the forehand. While he didn’t go crosscourt particularly often, he hit hard when he did. 22% of his crosscourt forehands ended the point in his favor with a winner or forced error. That shot can be a slightly favorable play against Baez–opponents win 47% of those points, compared to 45% for forehands overall–but only Nicolas Jarry has cleaned up against Baez in this category the way that Darderi did. It’s way too early to draw any conclusions about how the Italian’s game will fare on tour, but when you share the top of a forehand leaderboard with Jarry, you’re doing something right.

A big serve and a forehand isn’t enough: Nearly everybody has those, even if Darderi’s forehand has a bit of extra mojo. Upsetting the forehand-neutralizing Baez, especially in between victories against less complicated opponents, is a sign that the Italian has resources between his ears as well. Every week, it seems, Italian tennis looks a little bit better.

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Podcast Episode 104: The Present and Future of Jannik Sinner

Episode 104 of the Tennis Abstract Podcast, with Carl Bialik of the Thirty Love podcast, is our recap of the Miami Open, with a particular focus on the Italian teenager who reached the final there.

Jannik Sinner has a relatively weak first serve, but seems to do everything else right. We talk about how to balance what he is with what he could be, the importance of his evident emotional maturity, whether he’ll eventually win more first serve points, how well he’ll fare on clay this year, and just how much we can compare him with Rafael Nadal.

We also discuss the man who beat Sinner in the Miami final, Hubert Hurkacz. Is a 24-year-old without any obvious elite-level weapons still on the rise, or will the Masters 1000 title mark his career peak?

Thanks for listening!

(Note: this week’s episode is about 58 minutes long; in some browsers the audio player may display a different length. Sorry about that!)

Click to listen, subscribe on iTunes, or use our feed to get updates on your favorite podcast software.

Music: Everyone Has Gone Home by texasradiofish (c) copyright 2020. Licensed under a Creative Commons Attribution Noncommercial (3.0) license. Ft: spinningmerkaba

Podcast housekeeping:

  • The TAP book club will resume next week with Arthur Ashe’s memoir, Days of Grace. I’ve posted a few notes about Ashe and the book here. If you have thoughts or questions for us to consider, please let me know.
  • In case you haven’t heard, I’m 52 episodes into a short (~4 minute) daily podcast called Expected Points. Here’s today’s episode. I’m also doing a daily baseball podcast with the same format during the MLB season–check out The Opener.

Podcast Episode 102: Erik Jonsson on the Rising Wave of Stars in Men’s Tennis

Episode 102 of the Tennis Abstract Podcast welcomes back Erik Jonsson (@erktennis), previously heard on Episode 77 of the show in November of 2019.

Erik is a longtime Challenger and prospect watcher, and he shares his thoughts on Lorenzo Musetti, Aslan Karatsev, Jannik Sinner, Carlos Alcaraz, Sebastian Korda, and more. We talk about how to identify future tour-level stars by watching Challenger matches, whether there is any hope of another top-tenner as short as Diego Schwartzman, why Sweden hasn’t produced a female tennis superstar, what constitutes a legit top-20 player, and much more.

Thanks for listening!

(Note: this week’s episode is about 64 minutes long; in some browsers the audio player may display a different length. Sorry about that!)

Click to listen, subscribe on iTunes, or use our feed to get updates on your favorite podcast software.

Music: Everyone Has Gone Home by texasradiofish (c) copyright 2020. Licensed under a Creative Commons Attribution Noncommercial (3.0) license. Ft: spinningmerkaba

Podcast housekeeping:

  • The TAP book club is reading Arthur Ashe’s memoir, Days of Grace. I’ve posted a few notes about Ashe and the book here, and we’ll talk about it in a podcast episode next month.
  • I’m 43 episodes into a short (~4 minute) daily podcast called Expected Points. Here’s today’s episode. I’m doing a daily baseball show, too!

Andreescu, Medvedev, and the Future According to Elo

With the US Open title added to her 2019 trophy haul, Bianca Andreescu is finally a member of the WTA top 10, debuting at fifth on the ranking table. Daniil Medvedev, the breakout star of the summer on the men’s side, only cracked the ATP top 10 after Wimbledon. He’s now up to fourth. The official ranking algorithms employed by the tours take some time to adjust to the presence of new stars.

Elo, on the other hand, reacts quickly. While the ATP and WTA computers assign points based on a year’s worth of results (rounds reached, not opponent quality), Elo gives the most weight to recent accomplishments, with even greater emphasis placed on surprising outcomes, like upsets of top players. If your goal in using a ranking system is to predict the future, Elo is better: Elo-based forecasts significantly outperform predictions based on ATP and WTA ranking points.

Andreescu’s first Premier-level title came at Indian Wells in March, when she beat two top-ten players, Elina Svitolina and Angelique Kerber, in the semi-final and final. The WTA computer reacted by moving her up from 60th to 24th on the official list. Elo already saw Andreescu as a more formidable force after her run to the final in Auckland, so after Indian Wells, the algorithm moved her up to seventh. Three more wins in Miami, and the Canadian teen cracked the Elo top five.

Tennis fans are accustomed to the slow adjustments of the ranking system, so seeing a “(22)” or a “(15)” next to Andreescu’s name at Roland Garros and the US Open wasn’t particularly jarring. And there’s something to be said for withholding judgment, since tennis has had its share of teenage flashes in the pan. But Elo is usually right. The betting market heavily favored Serena Williams in the US Open final, but Elo saw the Canadian as the superior player, giving her a slight edge. After the latest seven match wins in New York, the algorithm rates Andreescu as the best player on tour, very narrowly edging out Ashleigh Barty. Would you dare disagree?

The launching (Ar)pad

When Medvedev first reached the top ten on the Elo list last October, I ran some numbers to compare the two ranking systems. Most players who earn a spot in the Elo top ten eventually make their way into the ATP top ten as well, but Elo is almost always first. On average, the algorithm picks top-tenners more than a half-year sooner than the tour’s computer. The 23-year-old Russian is a good example: He reached eighth place on the Elo list last October, but didn’t match that mark in the ATP rankings for another 10 months, after reaching the Montreal final.

Andreescu closed the gap faster than Medvedev did, needing a more typical six months to progress from Elo top-tenner to a single-digit WTA ranking. It may not take much longer before her Elo and WTA rankings converge at the top of both lists.

We no longer need Elo to tell us that Andreescu and Medvedev are likely to keep winning matches at the highest level. But having acknowledged the accuracy with which Elo glimpses the future, it’s worth looking at which players are likely to follow in their footsteps.

After the US Open, Elo’s boldest claim regards Matteo Berrettini, ranked sixth. The ATP computer sites him at 13th, and he only made one brief stop this summer inside the top 20. The Flushing semi-finalist has been inside the Elo top 10 since mid-June, and the algorithm currently puts him ahead of such better-established young players as Alexander Zverev and Stefanos Tsitsipas.

The women’s Elo list doesn’t feature any similar surprises in the top 10, but that hardly means it agrees with the WTA computer. Karolina Muchova, currently at a career-high WTA ranking of 43rd, is 23rd on the Elo table. Two veteran threats, Victoria Azarenka and Venus Williams, are also marooned outside the official top 40, but Elo sees them as 18th and 28th best on tour, respectively. In terms of predictiveness, quality is more important than quantity, so a limited schedule isn’t necessarily seen as a drawback. Elo is also optimistic about Sofia Kenin, rating her 13th, compared to her official WTA standing of 20th.

Half a year from now, I’d bet Berrettini’s official ranking is closer to 6 than to 13, and that Muchova’s position is closer to 23 than 43. It’s impossible to tell the future, but if we’re interested in looking ahead, Elo gives us a six-month head start on the official rankings. We’ll have to wait and see whether the rest of the women’s tour can keep Andreescu away from the top spot for that long.

How Good is Cori Gauff Right Now?

Italian translation at settesei.it

15-year-old sensation Cori Gauff holds a WTA ranking of No. 313. She has played only a limited number of events that are considered by the WTA’s system, so even before her impressive run began, we could’ve predicted that her ranking was an understatement. But by how much?

Gauff doesn’t show up yet on my Elo ratings list because, before Wimbledon qualies, she hadn’t played at least 20 matches at the ITF $50K level or higher in the last year. However, she still had a rating: 1,488, good for 194th place among those who had met the playing time minimum. A rating in that range translates to about a 3% chance of upsetting current top-ranked player Ashleigh Barty, and a 10% chance of beating someone around 20th, such as Donna Vekic. Given how little data we had to work with at that point, that seemed like a reasonable assessment.

Since she arrived in London, she has won six matches: Three in qualifying and three in the main draw, with wins over Venus Williams, Magdalena Rybarikova, and Polona Hercog. Not bad for a teenager who had previous won only one slam qualifying match and one tour-level main draw match in her young career!

194th place doesn’t seem like such a fair judgment anymore. Any player who comes through qualifying and reaches the fourth round at a major deserves some reassessment, and that’s even more applicable to a player about whom we knew so little two weeks ago. The tricky part is figuring out how much to adjust. Is Gauff now a top-100 player? Top 50? Top 20?

Revising with Elo

The Elo algorithm does a good job of approximating how humans make those reassessments: The more data we already have about a player, the less we will adjust her rating after a win or loss. The previous player to defeat Hercog was Simona Halep, at Eastbourne. We already have years’ worth of match results for Halep, and she was heavily favored to win the match. Thus, the fact that she recorded the victory alters our opinion of her by only a small amount. In Elo terms, it was an increase from 2,100 points to 2,102–basically nothing.

Gauff is a different story. Entering her third-round clash with Hercog, not only did we know very little about her skill level, it wasn’t even clear if she was the favorite. The result caused Elo to make a considerably larger adjustment, increasing her rating from 1,713 to 1,755, a rise 21 times greater than what Halep received after beating the same opponent. The 42-point jump caused her to leapfrog 16 players in the rankings.

Here is Gauff’s Elo progression, from the moment she arrived at Wimbledon to middle Sunday. After each match, I show her overall Elo (the numbers I’ve been discussing so far), her grass-specific Elo, and her grass-weighted Elo, a 50/50 blend of overall and grass-specific that is used for forecasting. For each of the three ratings, I also show her ranking among WTA players with at least 20 matches in the last 52 weeks.

Match          Overall   Rk  Grass   Rk  Weighted   Rk  
Pre-Wimbledon     1488  194   1350  163      1419  187  
d. Bolsova        1540  171   1405  132      1473  155  
d. Ivakhnenko     1566  157   1447  107      1507  131  
d. Minnen         1614  132   1514   57      1564   95  
d. Venus          1670  108   1578   40      1624   73  
d. Rybarikova     1713   83   1650   21      1682   41  
d. Hercog         1755   67   1686   17      1721   31

Over the course of only six matches, Gauff has jumped from 194th in the overall Elo rankings to 67th. For forecasting purposes, her grass court rating has soared from 187th to 31st. Her current weighted rating of 1,721 is better than that of three other women in the round of 16: Karolina Muchova, Carla Suarez Navarro, and Shuai Zhang. She trails another surviving player, Elise Mertens, by only 20 points.

So you’re telling me there’s a chance

Unfortunately, none of those relatively weak grass-court players are Gauff’s next opponent. Instead, the 15-year-old will face Halep, the third-best remaining player (behind Barty and Karolina Pliskova), and a three-time quarter-finalist at the All England Club. Halep’s weighted Elo rating is 229 points higher than Gauff’s, implying that the veteran has a 79% chance of winning on Monday. The betting market concurs, suggesting that the probability of a Halep victory is about 80%.

It doesn’t usually have much of an effect on forecasts to update Elo ratings throughout a tournament. While anyone reaching the 4th round has a higher rating than they did before the event, the differences are typically small. And since forecasts are based on the difference between the ratings of two players, the forecast isn’t affected if both players’ ratings have increased by roughly the same amount.

As a teenager with such limited match experience, Gauff breaks the mold. Her pre-Wimbledon 1,488 Elo rating is only two weeks old, and it is already completely unrepresentative of what we know of her skill level. She’ll have ample time to prove us right or wrong in the upcoming years, but for now, we have good reason to estimate that she belongs–even more than some of the older players who have reached the second week at Wimbledon.