Head-to-Heads – Heavy Topspin

The Riddle of the Ruud-Rublev Reversal

The story of the the 2024 ATP Tour Finals was the dominance of Jannik Sinner. I’ll refer you to what I wrote after the Australian Open: Yes, Jannik Sinner Really Is This Good. He just passed the 2,300 Elo threshold, becoming only the 12th man since Rod Laver to do so. When I update the Tennis 128 in a few weeks, he’ll be on it.

For all that, I’m preoccupied with something else. On the final day of round robin play, Casper Ruud beat Andrey Rublev to secure a place in the semi-finals. It was their eighth meeting and the Norwegian’s third victory:

Notice anything odd? Take away the unfinished Australian Open tilt, and the head-to-head breaks down precisely on surface lines. Rublev has won all four encounters on clay, while Ruud has run the table on hard courts. Not just any hard courts: indoors, at the Tour Finals.

We can look to external factors to explain some of the individual results. Casper had more at stake on Friday than the Russian did, with a chance to qualify for the final four. Rublev is older and broke through correspondingly earlier, so he was the natural favorite in their early meetings. Injuries and illness may have influenced another outcome or two, even aside from the retirement in Melbourne.

Still: 0-3 in completed matches for the ball-basher on hard courts, and 0-4 for the Roland Garros finalist on clay. Something’s going on here.

Not so fast

Rublev, to be fair, is hardly a fast-court specialist. His first tour-level title came on dirt in Umag, and he picked up a Masters crown last year in Monte Carlo, on one of the circuit’s slowest surfaces. The Russian’s forehand is a weapon in any conditions, and slow courts can disguise some of his weaknesses.

On the other hand, however much Rublev likes the dirt, Ruud likes it more. Earlier this year, I quantified the notion of “surface sensitivity,” the degree to which a player’s results are influenced by court speed. Rublev scored at -2.2, indicating that he does better on slower surfaces, a bit more so than the typical tour regular. Casper was considerably further down the list, at -5.0. The rating tells us that he’s more receptive to slow courts than Pablo Carreno Busta or Jaume Munar. He’s grades about the same as Diego Schwartzman.

Maybe the oddball head-to-head is a quirk of when the pair have met? Not all hard courts play fast, and not all clay behaves like the crushed brick at Roland Garros. Here are the venues for the seven completed meetings, along with my ace-based surface speed rating for each. Ratings above 1 are faster than average, below 1 are slower:

Year  Tournament   Winner  Speed  
2024  Tour Finals  Ruud     1.36  
2023  Bastad       Rublev   0.86  
2022  Tour Finals  Ruud     1.50  
2021  Tour Finals  Ruud     1.51  
2021  Monte Carlo  Rublev   0.54  
2020  Hamburg      Rublev   0.52  
2019  Hamburg      Rublev   0.74

Hypothesis denied! The 2021 and 2022 Tour Finals were the fastest conditions of their respective years, while Monte Carlo was the slowest of the entire 2021 season. Last year’s Bastad surface was fairly neutral for a clay court, but the rest of the Ruud-Rublev showdowns took place on fast hard courts or slow clay.

We could always mark down a string of seven surface-confounding results to luck, especially when both players are capable in all conditions. But it would be far more satisfying to find an explanation that tells us something about the players and their particular skills.

Stoppable

We don’t have to look far. Here are Casper’s win rates on first and second serve points against Rublev, separated by surface:

Surface  1st W%  2nd W%  
Clay      56.8%   48.4%  
Hard      72.7%   50.7%

Everybody wins fewer first serve points on clay than on hard courts, but not like this. The average gap for top-50 players in 2024 is four percentage points–not sixteen. At tour level against the entire field, Ruud has shown an even smaller difference, winning 73.1% of hard-court first-serve points against 71.2% of those on clay.

Rublev is not a brilliant returner. He’s a serviceable one with tactics to match. He often struggles to get first serves back in play. On second serve, he’s unafraid to unleash his weapons, accepting some errors in exchange for tilting other points in his favor. On clay, he’s able to turn a few more first serves into rally openers. In 2024, his gap between clay and hard-court first-serve return points won was bigger than average. But not nearly as wide as it is against Casper.

When it works…

Ruud, like many men who have developed into strong clay-courters, doesn’t have a monster serve. He can place it, he can disguise it, and he knows how to play behind it. On a fast hard court, those skills–combined with a bit more risk-taking–can result in numbers that look more like those of a big server. Against Rublev last week, he won just shy of 80% of his serve points, supported by 15 aces.

When the Norwegian is hitting corners and the ball is skimming off a court like the speedy one in Turin, Rublev is helpless. Over his career, according to the nearly 200 matches logged by the Match Charting Project, he puts 58% of first serves back in play. Against Casper on Friday, he didn’t manage 50%–a repeat of his performance on the same court two years earlier.

Rublev’s first-serve-return struggles on hard court contrast with how he feasts on Ruud’s serve on clay. The next table shows the rate at which the Russian puts Casper’s first serves in play, as well as his win percentage when he does so:

Match                Result  1st: RiP%  RiP W%  
2024 Tour Finals RR       L      46.9%   43.3%  
2023 Bastad F             W      64.6%   61.3%  
2022 Tour Finals SF       L      45.7%   50.0%  
2021 Tour Finals RR       L      67.5%   51.9%  
2021 Monte Carlo SF       W      84.4%   59.3%  
2020 Hamburg SF           W      91.4%   59.4%

The exception to the rule here is the 2021 Tour Finals match, which ended in a third-set tiebreak. It was the closest either man has come to securing one of the matches he “should” have won. Rublev won 52.9% of total points, but Ruud served his way out of just enough jams to come through.

On the very slow Monte Carlo and Hamburg courts, Rublev’s ability to handle the Norwegian’s first serve meant that Ruud was left with no edge whatsoever. Casper might be the superior baseliner, but he started too many points at a disadvantage. The picture might look different if they played on slow clay today, since Ruud is stronger and tactically savvier on serve. But I imagine it would still be a struggle, one in which few of Casper’s service games would sail by quickly.

Pundits like to say that tennis is a game of matchups. They often overstate their case: The better player (by ranking, or Elo rating, or whatever) usually wins. When they don’t, it isn’t always because of some quirk in the head-to-head. With Rublev and Ruud, though, such a quirk dictates the results. Few men are able to erase Rublev’s advantage on a hard court as much as the Norwegian can. Casper’s first serve is rarely so ineffectual as when the Russian is waiting for it on dirt. Ruud is set for another big European clay swing next year–so long as his buddy Andrey lands in the other half of the draw.

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With Tommy Paul, Get Ready To Backhand

On Sunday, Tommy Paul won the Stockholm final with one well-executed tactic. He hammered the Grigor Dimitrov backhand, shot after shot, point after point. Paul hit 71% of his backhands cross-court, far above the tour average of 50%. He also aimed his forehands at Dimitrov’s weaker side, going inside-out with 38% of his forehands, compared to the typical clip of 24%.

The results: 6-4 6-3 to the American, and a paltry seven rally winners for his opponent. Dimitrov was forced to hit backhands for 58% of his non-return groundstrokes, compared to his usual hard-court rate of 43%.

Paul doesn’t have any overwhelming weapons of his own, so he wins matches–42 of them already this year–by neutralizing opponents. In the case of Sunday’s final, that meant putting pressure on a backhand that is more flashy than effective. Dimitrov’s signature one-hander is not the worst on tour, but it is not much of an asset. His career backhand potency (BHP) is negative, meaning it costs him more points than it gains. Paul’s elite movement allowed him to exploit a weakness that the Bulgarian can usually hide.

Grigor isn’t the only man on tour with a preference for the forehand. Even players with top-tier backhands will often opt for a forehand because of the angles it opens up. Paul’s ability to pepper the backhand, then, is often on display. Facing Jannik Sinner at the US Open, the American hit 60% of his backhands cross-court–good enough to push the world number one to two tiebreaks. At Indian Wells against Casper Ruud, he hit 61% of his backhands cross-court. That proved successful enough to secure his first top-ten win of the season.

Few pros play like this. Or more accurately: Few men are able to play like this. The Match Charting Project has at least 20 hard-court righty-versus-righty matches for almost 100 different men. Here are the top 15, ranked by how often they hit backhands cross-court.

Player                 BH XC%  
Lleyton Hewitt          70.0%  
Andre Agassi            65.9%  
Marat Safin             62.8%  
Yevgeny Kafelnikov      62.8%  
Richard Gasquet         59.8%  
Daniil Medvedev         59.4%  
Jenson Brooksby         59.3%  
James Blake             59.0%  
Kei Nishikori           58.7%  
Pete Sampras            58.6%  
Tommy Paul              58.6%  
Borna Coric             58.1%  
David Ferrer            58.0%  
Juan Martin del Potro   58.0%  
David Nalbandian        57.9%

That’s pretty good company. The active players highest on the list–Medvedev and Gasquet–are known for camping out far behind the baseline, giving them extra time to choose their shot. Paul and Nishikori (and the category-busting Brooksby) act faster. They rely on anticipation, footwork, and racket control to direct the ball where their opponent doesn’t want it to go.

Here’s a similar list–again, out of 100 or so players–ranked by inside-out forehand frequency. Same goal, different shot:

Player                 FH IO%  
Milos Raonic            39.5%  
Jack Sock               38.4%  
John Isner              38.1%  
Jim Courier             37.9%  
Reilly Opelka           33.3%  
Robin Haase             33.1%  
Andrey Rublev           33.0%  
Holger Rune             32.5%  
Daniel Evans            32.3%  
David Ferrer            32.3%  
Marin Cilic             31.8%  
Felix Auger-Aliassime   31.7%  
Thanasi Kokkinakis      31.6%  
Fabio Fognini           31.3%  
Kevin Anderson          31.1%  
Jo-Wilfried Tsonga      30.6%  
James Blake             30.1%  
Roberto Bautista Agut   30.0%  
Matteo Berrettini       29.9%  
Tommy Paul              29.7%

Many of these men make the list because they prey on weak service returns, or because they play high-risk shots when running around their backhands. Despite standing outside those categories, Paul ranks high on this metric as well. There’s very little overlap between the two lists: Only James Blake ranks above Tommy on both.

In short: Everybody (usually) wants to hit to the backhand, but few men are able to do so as often as Tommy Paul.

When tactics fail

Stockholm trophy in tow, Paul took his winning streak to Vienna. He began his campaign yesterday against compatriot Brandon Nakashima. Nakashima has become a thorn in Paul’s side, with three previous tour-level wins on three different surfaces. Tommy’s only victory came at a Challenger in 2019, when Nakashima was and 18-year-old ranked 942nd in the world.

Nothing changed this week. Nakashima secured a 6-4, 6-4 victory and improved his record against the older man to 4-1. Paul unleashed the same tactical plan that he used to beat Dimitrov, and he discovered–not for the first time–that it isn’t so effective against a sturdier backhand.

Paul hit nearly as many backhands cross-court as he did in the Stockholm final. But unlike Dimitrov, Nakashima was able to go toe-to-toe from that corner. Dimitrov went to the slice nearly half the time–opening up, incidentally, many of the opportunities Paul seized to hit inside-out forehands. Nakashima hit the slice barely half as often. 12% of Dimitrov’s topspin backhands became unforced errors; only 5% of Nakashima’s did.

*Nakashima took the tournament’s (unfortunately phrased) advice.*

We can’t explain the entire result based on Paul’s tactical preference. He looked sluggish throughout, coughing up 31 unforced errors compared with just 20 in the Stockholm final. But causation can run multiple directions: Nakashima didn’t allow him to play the clean, logical game that earned him the trophy in Sweden. The veteran scuffled to find another solution.

Another of Tommy’s worst matchups has a similar profile. He is 0-5 against Alex de Minaur, whose backhand also rarely lets him down. Both times they met in 2023, Paul hit his backhand cross-court more than 62% of the time. In Acapulco, the American hit his forehand inside-out more than 40% of the time, the highest mark we have for him in the Match Charting Project database. De Minaur doesn’t blow him off the court, so Paul can hit the shots he wants. Those shots–regardless of the Aussie’s own traits–are aimed at the backhand corner.

But against a player like Nakashima or de Minaur, the tactic doesn’t work. Lots of inside-out forehands are a safe bet against a player like Dimitrov, but de Minaur’s defense is too good. In Acapulco, Paul won only half of those inside-out forehands, well below tour average. The American generally played the way he wanted to, forcing de Minaur to hit a whopping 66% of his rally groundstrokes from the backhand side in their Los Cabos meeting. But the Aussie didn’t mind. At least in those matches, Paul showed little sign of a plan B.

Another dilemma for Tommy arises when someone takes away his plan A. The only other player who has defeated him five times is Andrey Rublev, hardly a man you’d select to run a backhand clinic. We don’t yet have any charted matches from this head-to-head, but it’s easy to speculate what goes wrong for Paul. In order to hit a disproportionate number of shots to a particular location, you need to have some control over the proceedings. Rublev, with his devastating forehand and aggressive mindset, is one of the few players on tour who can outslug the American’s speed.

The American’s losses are a good illustration of just how hard it is to excel at the highest levels of professional tennis. He is perhaps as good as anyone in the game at taking and keeping control of rallies from the baseline. But even that world-class skill can be nullified by a howitzer forehand or a backhand like a brick wall. Paul has twice upset Carlos Alcaraz, but when handed a first-round opponent with a solid backhand, as he was yesterday in Vienna, he sometimes finds that his best isn’t good enough.

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Surface Sensitivity and Ugo Humbert’s Serve

*Ugo Humbert in 2023. Credit: Hameltion*

Let’s start off with a couple of puzzles. I realize they aren’t the sort of things that keep most of you up at night, but they were odd enough to drive me to a flurry of coding, data analysis, and now blog writing.

On Wednesday, Ugo Humbert lost his first-round match in Rotterdam to Emil Ruusuvuori. It marked an unceremonious end to a hot streak for Humbert: He not only won the title in Marseille last week–launching himself into the Elo top ten–but he strung together 31 consecutive holds. 1,000 kilometers north, on a different indoor hard court, he got broken twice by a man ranked outside the top 50.

That’s the first puzzle: Why did the Frenchman lose? Again, it’s not that odd, as my Elo ratings gave Ruusuvuori a one-in-three shot to pull the upset. But it’s a match that Humbert should have won.

Head-scratcher number two: Why does Humbert always lose to Ruusuvuori? Wednesday’s decision marked their fifth meeting, and the Finn is undefeated. While the outcome is always close–Rotterdam was their fourth deciding set, and the other match went to two tiebreaks–the results are starting to get boring. Ruusuvuori is a solid player, and he is consistently able to blunt the Frenchman’s serve. But five in a row?

The answer to both mysteries is the same, and it’s more satisfying than I expected. Rotterdam is unusually slow for a hard court, especially indoors. Like most (or perhaps all) of the previous Humbert-Ruusuvuori venues, it plays slower than tour average. Just as important, Humbert’s game is unusually sensitive to surface speed. While that isn’t always true of big servers, he stands out as a fast-court specialist. We couldn’t have confidently predicted a Finnish upset, but we could have guessed that the Marseille champion would find this week’s tournament tougher going.

Rotterdam, it’s slow

The last time I published surface speed numbers, in late 2019, Rotterdam rated as the slowest indoor hard court on tour. Adjusting for the mix of players at the event, there were 10% fewer aces at the tournament than expected. It was a sharp decline from 2017 and 2018, when the venue sported more typically speedy indoor conditions.

Since then, the results have remained similar. Last year, the rate was 5% lower than expected, roughly tied with Stockholm as the slowest indoor surface on tour. Marseille, by contrast, gave players 12% more aces than usual.

There are limitations to using aces as a proxy for surface speed; I use aces because it’s the most relevant data that is widely available. Still, while you can quibble about the methodology or about a specific tournament’s place on the list, the overall rank order seems about right. Aces–adjusted for each event’s field–tell you much of the story.

With a growing mass of Match Charting Project data, we can do a little better. We have shot-by-shot logs for over one thousand matches since 2021. To compare conditions, I used my Serve Impact metric, which estimates how many points a player wins, directly or indirectly, because of his serve. It counts aces, other unreturned serves, and a fraction of the service points that take longer to decide. Depending on your motivation in measuring court speed, this isn’t perfect either: It doesn’t directly tell you anything about bounce height, for instance. But if you want to know what sort of players a tournament favors, Serve Impact gets you close.

By this more sophisticated metric, Rotterdam is… still slow. The venue takes away 4% of the points a player typically earns from his serve. Marseille and Montpellier each swing 7% in the other direction, Stockholm and Vienna provide a modest 3% boost, and Basel adds 8% to the server’s punch. With the exception of the short-lived tour stop in Gijon, Rotterdam has been the slowest indoor hard court of the 2020s. Even the clay in Lyon plays faster.

Here are the Serve Impact adjustments for the tournaments best represented in the dataset. Higher numbers mean faster conditions with more points decided based on the serve:

Tournament            ServeImpact  
Stuttgart                    1.29  
NextGen Finals               1.20  
Tour Finals                  1.16  
Wimbledon                    1.11  
Shanghai Masters             1.11  
Halle                        1.10  
Queen's Club                 1.08  
Basel                        1.08  
Washington                   1.08  
Dubai                        1.07  
                                   
Tournament            ServeImpact  
Antwerp                      1.05  
Gstaad                       1.05  
Australian Open              1.04  
Davis Cup Finals             1.04  
Cincinnati Masters           1.04  
Paris Masters                1.03  
Vienna                       1.03  
Miami Masters                1.02  
Madrid Masters               1.01  
US Open                      1.01  
                                   
Tournament            ServeImpact  
Canada Masters               1.00  
Rotterdam                    0.96  
Indian Wells Masters         0.95  
Rome Masters                 0.92  
Acapulco                     0.87  
Barcelona                    0.87  
Roland Garros                0.83  
Monte Carlo Masters          0.83

Average Serve Impact is around 34%, so the 4% hit in Rotterdam knocks that down to about 32.6%. Humbert has an above-average serve, so the slow-court penalty is greater still. He isn’t going to win any awards for rallying prowess, especially against someone as sturdy as Ruusuvuori, so the points that he doesn’t secure with his serve will disproportionately go against him.

The first three meetings in the Humbert-Ruusuvuori head-to-head were on clay, at Roland Garros, Madrid, and Rome. The fourth came on grass, at ‘s-Hertogenbosch. It rates a bit faster from 2021-23 than Halle or Queen’s Club by the Serve Impact metric, though it rated as the slowest grass court on tour last year by my older ace-rate algorithm. Maybe it was less server-friendly in 2023, just in time for Humbert to be flummoxed once again.

Surface sensitivity

We tend to take for granted that players are suited to conditions in predictable ways. Big servers like fast surfaces, right? Broadly speaking, yes, but it’s not a hard-and-fast rule. Bounce height makes a difference, footwork matters, and some players are just more comfortable on some surfaces than others.

Armed with surface speed ratings, this is something we can test. If a player is particularly sensitive to conditions, each tournament’s Serve Impact rating should have a predictable influence on his match outcomes. I tried that for all tour regulars, controlling for player strength by using overall Elo ratings at the time of each match.

The resulting numbers are an abstraction on top of an abstraction, so they’re a bit difficult to get your head around. I’ve tried to simplify matters by rendering them in terms of Elo points. A player who is very sensitive to surface and does better on hard courts is, effectively, a better player in faster conditions. The ‘Sensitivity’ numbers given here are the benefit–denominated in Elo points–of each single percentage point that a surface is faster than average. For players who like it slow, negative numbers express the same idea, the Elo-point advantage of a one-percentage-point slowdown.

Here is the list of all players with at least 100 tour-level matches since 2021, plus Rafael Nadal:

Player                       Sensitivity  
Tallon Griekspoor                   11.1  
Ugo Humbert                          9.5  
Richard Gasquet                      9.1  
Novak Djokovic                       8.7  
Adrian Mannarino                     7.9  
Sebastian Korda                      4.9  
Jordan Thompson                      4.3  
Matteo Berrettini                    4.0  
Aslan Karatsev                       3.6  
Tommy Paul                           3.4  
Marcos Giron                         2.9  
Marton Fucsovics                     2.9  
Marin Cilic                          2.6  
Felix Auger-Aliassime                2.1  
Hubert Hurkacz                       1.7  
                                          
Player                       Sensitivity  
Frances Tiafoe                       1.6  
Carlos Alcaraz                       1.4  
Emil Ruusuvuori                      1.3  
Brandon Nakashima                    1.3  
Cristian Garin                       0.6  
Alexander Zverev                     0.5  
Alexander Bublik                     0.5  
Ilya Ivashka                         0.0  
Arthur Rinderknech                  -0.1  
Taylor Fritz                        -0.3  
Jan Lennard Struff                  -0.3  
Lorenzo Sonego                      -0.4  
Mackenzie Mcdonald                  -0.5  
Andy Murray                         -0.9  
Grigor Dimitrov                     -1.1  
                                          
Player                       Sensitivity  
Roberto Bautista Agut               -1.2  
Alex de Minaur                      -1.2  
Karen Khachanov                     -1.4  
Jannik Sinner                       -1.4  
Yoshihito Nishioka                  -1.5  
Miomir Kecmanovic                   -1.9  
Andrey Rublev                       -2.2  
Daniel Evans                        -2.2  
Cameron Norrie                      -2.5  
Holger Rune                         -2.9  
Roberto Carballes Baena             -3.0  
Botic van de Zandschulp             -3.1  
Daniil Medvedev                     -3.4  
Denis Shapovalov                    -3.5  
Sebastian Baez                      -3.7  
                                          
Player                       Sensitivity  
Laslo Djere                         -4.1  
Dusan Lajovic                       -4.1  
Pablo Carreno Busta                 -4.4  
Jaume Munar                         -4.6  
Fabio Fognini                       -4.8  
Nikoloz Basilashvili                -4.9  
Casper Ruud                         -5.0  
Diego Schwartzman                   -5.4  
Francisco Cerundolo                 -5.9  
Alexei Popyrin                      -6.4  
Albert Ramos                        -6.8  
Rafael Nadal                        -9.9  
Alejandro Davidovich Fokina        -10.1  
Stefanos Tsitsipas                 -10.2  
Lorenzo Musetti                    -11.2

There’s Ugo! He’s not quite as surface sensitive as Tallon Griekspoor, but a couple of points is within the margin of error. A sensitivity rating of 9.5 means that Humbert is about 100 Elo points worse in Rotterdam than he is Marseille, as long as I’ve accurately estimated the server-friendliness of the respective playing conditions. Ruusuvuori may also like it faster, but only marginally so; he’s effectively neutral.

Keen-eyed readers may have noted that I earlier referred to “overall” Elo. I’m not using surface-specific Elo ratings here, because I don’t want to adjust for surface twice. Surface-specific ratings already capture some of this: Humbert’s hElo (for hard courts) is 120 points higher than his cElo (for clay courts), which tallies reasonably well with these more fine-grained distinctions. What hElo and cElo can’t tell us, though, is how much his (or anyone else’s) performance will vary on the same surface, depending on the conditions at each specific venue.

It’s easy to get lost in the weeds of Elo-based forecasting calculations, but it’s important to remember they are just tools to help measure a real-world phenomenon. Not every big server is equally at sea on clay; some dirtballers are less dependent on slow conditions than others. Small differences in surface speed are, for most matchups, a minor consideration. But for some players, conditions matter a lot. Ugo Humbert likes his surfaces fast, as much as almost anyone else on tour. In Rotterdam, the conditions did not cooperate.

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Are Tournament Draws Giving Us Suspiciously Many Venus-Serena Clashes?

This week in Lexington, top seed Serena Williams faces her sister, Venus Williams, in the second round. They are both among the all-time greats, and they have played each other nine times in grand slam finals, so it’s always jarring to see them turn up in the same section of a draw and play on a Thursday.

Lately, their encounters seem to always happen long before the business end of a tournament. Their three matches between the 2017 Australian Open final and this week in Lexington all happened in the round of 32, including a planned 2019 Rome meeting from which Serena withdrew. Venus is usually unseeded, no longer the world-beater she once was, so it is at least possible that the Williams sisters would be bracket neighbors in any given week.

But should it happen quite so often? It is an understatement to say that Serena and Venus were not universally embraced upon arrival in the tennis world. If you’re conspiracy minded, every tournament draw is an opportunity to commit dastardly deeds. Perhaps early in the Williams era, it was the work of racist or otherwise misguided tournament officials who wanted to avoid all-Williams finals. Or nowadays, event honchos recognize that Venus is unlikely to reach the final, so they tinker with the bracket to make a headline-grabbing Williams-versus-Williams clash more likely.

I’m sure that most draws are conducted on the up-and-up, but the process is sufficiently opaque that it’s easy to get suspicious. It’s also easy to make mistaken generalizations from insufficient data. Let’s see what the numbers can tell us.

150 tournaments!

Lexington is the 150th tour event with both Serena and Venus in the field.*

* I think. My WTA data isn’t perfect for the early years of their careers, and there was an uncomfortable amount of manual tabulation involved in this post. Their TennisAbstract player pages are missing the 1999 Grand Slam Cup, but I’ve included it in all the numbers here. For the purposes of doing analytics, it doesn’t matter much if the total is 148 or 151, but if you’re printing a banner or making a cake, you should double-check.

Thursday’s match in Lexington will be their 31st, plus one withdrawal apiece. In 13 of the 150 events, the Williams sisters were either the top two seeds or the 3rd and 4th seeds, meaning that draw shenanigans were out of the question–they could not face each other until the final. 4 of those 13 times, that’s exactly what they did.

What are the odds?*

* Of me being able to use this sub-heading in any given blog post?

I went through the remaining 137 tournaments and identified the round in which they either did meet or could have met. For the purposes of analyzing draws, there isn’t really a difference. For instance, Serena and Venus have landed in the same half 73 out of a possible 137 times, a bit more than the 68 or 69 times that we would expect.

Because of their seeds, they had the chance of ending up in the same quarter 116 times, and that’s how it worked out 28 times, just under the 29 times that an exact one-in-four rate would’ve given them. The smaller the draw section, the fewer tournaments that Serena’s and Venus’s seeds made it possible for them to meet.

I counted the number of tournaments with a possible meeting on or before a certain round, and then the number of events in which the draw delivered that meeting, regardless of whether both Williamses got that far. Here are the results, along with the probability of that many or more actual meetings:

Section  Possible  Actual  Chance  
Half          137      73     25%  
Quarter       116      28     62%  
Eighth         85      17      3%  
16th           64       5     37%  
32nd           42       1     74%

There’s a one-in-four chance that Serena and Venus would’ve landed in the same half as many times as they have throughout their entire careers. That’s a bit of bad luck, but it’s hardly a smoking gun. The same is true for the same quarters, as well as very early meetings that would pit them against each other in the round of 32 or 64.

That leaves one eyebrow-raising number to discuss. On 85 occasions, at least one of the two women was seeded outside the top eight, making possible a meeting in the round of 16 or earlier. Given random draws, we’d expect 10 or 11 brackets in which they could face each other so early. Instead, we got 17.

A 3% chance of so many early encounters isn’t quite as bad as it sounds. I’ve tried to walk you through this process in the way I approached it. While I wondered if Serena and Venus have met more often than random draws would normally deliver, I didn’t have a particular round in mind. As you’ve seen, I generated a bunch of numbers, and one of the five looked suspicious. You might be able to construct a story that explains why the round of 16 is different from the others (such as my theory that tournament directors want mid-week headlines), but because we generated so many numbers, we were that much more likely to end up with an extreme percentage simply by chance.

The smoking (nerf) gun

Thus, we’re able to raise the possibilities that some draws weren’t random, but we can hardly prove it. One problem–one that we could’ve foreseen from the get-go–is that some draws are definitely not tampered with. Probably most draws. And even if they were, most tournaments wouldn’t have any reason to mess with Serena’s or Venus’s placement in the bracket. Or if they did, they might prefer an all-Williams final, and thus alter the bracket in the opposite direction of what we’re hunting for.

If you like conspiracy hunting, I’ve got a tiny sample for you. Since the beginning of 2018, Venus and Serena have played in the same tournament 15 times, and their seedings (or lack thereof) made it possible for them to be drawn in the same eighth 14 of those times. Of the 14, they were placed in position for a round-of-16 or earlier meeting 5 times. There’s only a 2% chance of that … if you set aside the fact that I’m checking all sorts of subsets of matches looking for (probably spurious) patterns. If nothing else, the 5-of-14 figure explains why it seems like Serena and Venus keep landing in the same draw sections lately. They do!

Broadly speaking, then, this is all much ado about nothing. (I don’t even know if these conspiracy theorists exist, so maybe I just invented a conspiracy and spent my evening debunking it. Hooray?) It’s possible that a few tournament directors are producing non-random draws … but it would take a very different kind of investigative work to prove it. Worst case scenario, we get a few more Serena-Venus matches. It may not be fair to the older sister, but it’s a pretty good deal for tennis fans.

Will a Back-To-Normal Federer Backhand Be Good Enough?

Italian translation at settesei.it

After Roger Federer’s 2017 triumph over Rafael Nadal at the Australian Open, I credited his narrow victory to his backhand. He came back from the injury that sidelined him for the second half of 2016 having strengthened that wing, ready with the tactics necessary to use it against his long-time rival. Since that time, he has beaten Nadal in five out of six meetings, suggesting that the new-and-improved weapon has remained a part of his game.

The Swiss is riding high after defeating Rafa once again in the Wimbledon semi-finals on Friday. But unlike in Melbourne two-and-a-half years ago, the backhand wasn’t responsible for the victory. In the Australian Open final, Federer’s stylish one-hander earned him 11 more points than in a typical contest, enough to flip the result in his favor. On Friday, Nadal had little reason to fear a Federer backhand that was only a single point better than average. The Swiss owes his semi-final result to some stellar play, but not from his backhand.

BHP redux

I’m deriving these numbers from a stat called Backhand Potency (BHP), which uses Match Charting Project shot-by-shot data to isolate the effect of each one of a player’s shots. The formula is straightforward:

[A]dd one point for a winner or an opponent’s forced error, subtract one for an unforced error, add a half-point for a backhand that set up a winner or opponent’s error on the following shot, and subtract a half-point for a backhand that set up a winning shot from the opponent. Divide by the total number of backhands, multiply by 100, and the result is net effect of each player’s backhand.

The average player hits about 100 backhands per match, so the final step of multiplying by 100 gives us an approximate per-match figure. BHP hands out up to 1.5 “points” per tennis point, since credit is given for both a winning shot and the shot that set it up. Thus, to translate BHP (or any other potency metric, like Forehand Potency, FHP) to points, multiply by two-thirds. In the 2017 Australian Open final, Federer’s backhand was worth +17 BHP, equal to about 11 points.

On Friday, Roger’s backhand was worth only +1 BHP. The best thing we can say about that is that it didn’t hold him back–the sort of comment we might have made as he racked up wins for the first 15 years of his career.

The semi-final performance wasn’t an outlier. In a year-to-year comparison based on the available (admittedly incomplete) MCP data, the 2019 backhand looks an awful lot like the pre-injury backhand:

Year(s)     BHP  
1998-2011  +0.1  
2012       +0.4  
2013       -1.8  
2014       -1.1  
2015       +1.3  
2016       -0.3  
2017       +3.5  
2018       +1.3  
2019       +0.8

There are still good days, like Fed’s whopping +16 BHP against Kei Nishikori in this week’s quarter-finals. But when we tally up all the noise of good and bad days, effective and ineffective opponents, and fast and slow conditions, the net result is that the backhand just doesn’t rack up points the way it did two years ago.

The backhand versus Novak

Federer’s opponent in today’s final, Novak Djokovic, is known for his own rock-solid groundstrokes. Like Nadal did for many years, Djokovic is able to expose the weaker side of Federer’s baseline game. The Serbian has won the last five head-to-head meetings, and nine of the last eleven. In most of those, he reduces Roger’s backhand to a net negative:

Year  Tournament        Result  BHP/100  
2018  Paris             L         -11.0  
2018  Cincinnati        L         -11.0  
2016  Australian Open   L         -12.6  
2015  Tour Finals (F)   L          -4.8  
2015  Tour Finals (RR)  W          +0.7  
2015  US Open           L          +0.8  
2015  Cincinnati        W          -2.2  
2015  Wimbledon         L         -13.4  
2015  Rome              L         -12.2  
2015  Indian Wells      L          -5.0  
2015  Dubai             W          -5.9  
…                                        
2014  Wimbledon         L          -3.1  
2012  Wimbledon         W          +9.6

Out of 438 charted matches, Federer’s BHP was below -10 only 27 times. On nine of those occasions–and two of the five since Fed’s 2017 comeback–the opponent was Djokovic. Incidentally, Novak would do well to study how Borna Coric dismantles the Federer backhand, as Fed suffered his two worst post-injury performances (-20 at 2018 Shanghai, and -19 at 2019 Rome) against the young Croatian.

It is probably too much to ask for Federer to figure out how to beat Djokovic at his own game. The best he can do is minimize the damages by serving big and executing on the forehand. The Swiss has a career average +9 Forehand Potency (FHP), but falls to only +4 FHP against Novak. In last year’s Cincinnati final, Djokovic reduced his opponent to an embarrassing -13 FHP, the worst of his career. It wasn’t a fluke: four of Fed’s five worst single-match FHP numbers have come against the Serb.

If Federer is to win a ninth Wimbledon title, he’ll need to rack up points on at least one wing–either his typical forehand, or the backhand in the way he did against Djokovic in the 2012 semi-final. Whichever one does the damage, he’ll also need the other one to remain steady. His forehand was plenty effective in the semi-final against Nadal, worth +12 FHP in that match. Against a player like Novak who defends even better on a fast surface, Federer will need to somehow tally similar results. It’s a lot to ask, and one thing is certain: No one would be able to complain that his 21st major title came cheaply.

Slow Conditions Might Just Flip the Outcome of Federer-Nadal XL

Italian translation at settesei.it

Roger Federer likes his courts fast. Rafael Nadal likes them slow. With eight Wimbledon titles to his name, Federer is the superior grass court player, but the conditions at the All England Club have been unusually slow this year, closer to those of a medium-speed hard court.

On Friday, Federer and Nadal will face off for the 40th time, their first encounter at Wimbledon since the Spaniard triumped in their historical 2008 title-match battle. Rafa leads the head-to-head 24-15, including a straight-set victory at his favorite slam, Roland Garros, several weeks ago. But before that, Roger had won five in a row–all on hard courts–the last three without dropping a set.

Because of the contrast in styles and surface preferences, the speed of the conditions–a catch-all term for surface, balls, weather, and so on–is particularly important. Nadal is 14-2 against his rival on clay, with Federer holding a 13-10 edge on hard and grass. Another way of splitting up the results is by my surface speed metric, Simple Speed Rating (SSR). 22 of the matches have been been on a court that is slower than tour average, with the other 17 at or above tour average speed:

Matches     Avg SSR  RN - RF  Unret%  <= 3 shots  Avg Rally  
SSR < 0.92     0.74     17-5   21.2%       49.5%        4.7  
SSR >= 1.0     1.14     7-10   27.0%       56.9%        4.3

At faster events–all of which are on hard or grass–fewer serves come back, more points end by the third shot, and the overall rally length is shorter. Fed has the edge, with 10 wins in 17 tries, while on slower surfaces–all of the clay matches, plus a handful of more stately hard courts–Rafa cleans up.

Rafa broke Elo

According to my surface-weighted Elo ratings, Federer is the big semi-final favorite. He leads Nadal by 300 points in the grass-only Elo ratings, which gives him a 75% chance of advancing to the final. The betting market strongly disagrees, believing that Rafa is the favorite, with a 57% chance of winning.

The collective wisdom of the punters is onto something. Elo has systematically underwhelmed when it comes to forecasting the 39 previous Fedal matches. Federer has more often been the higher-rated player, and if Roger and Rafa behaved like the algorithm expected them to, the Swiss would be narrowly leading the head-to-head, 21-18. We might reasonably conclude that, going into Friday’s semi-final, Elo is once again underestimating the King of Clay.

How big of Fedal-specific adjustment is necessary? I fit a logit model to the previous 39 matches, using only the surface-weighted Elo forecast. The model makes a rough adjustment to account for Elo’s limitations, and reduces Roger’s chances of winning the semi-final from 74.8% all the way down to 48.5%.

Now, about those conditions

The updated 48.5% forecast takes the surface into account–that’s part of my Elo algorithm. But it doesn’t distinguish between slow grass and fast grass.

To fix that, I added SSR, my surface speed metric, to the logit model. The model’s prediction accuracy improved from 64% to 72%, its Brier score dropped slightly (a lower Brier score indicates better forecasts), and the revised model gives us a way of making surface-speed-specific forecasts for this matchup. Here are the forecasts for Federer at several surface speed ratings, from tour average (1.0) to the fastest ratings seen on the circuit:

SSR  p(Fed Wins)  
1.0        49.3%  
1.1        51.4%  
1.2        53.4%  
1.3        55.5%  
1.4        57.5%  
1.5        59.5%

In the fifteen years since Rafa and Roger began their rivalry, the Wimbledon surface has averaged around 1.20, 20% quicker than tour average. In 2006, when they first met at SW19, it was 1.24, and in 2008, it was 1.15. Three times in the last decade it has topped 1.30, 30% faster than the average ATP surface. This year, it has dropped almost all the way to average, at 1.00, when both men’s and women’s results are taken into account.

As the table shows, such a dramatic difference in conditions has the potential to influence the outcome. On a faster surface, which we’ve seen as recently as 2014, Federer has the edge. At this year’s apparent level, the model narrowly favors Nadal. Rafa has said that the surface itself is unchanged, but that the balls have been heavier due to humidity. He should hope for another muggy day on Friday–the end result could depend on it.

Trivia: Deja Vu All Over Again

Italian translation at settesei.it

In the last several days, Fernando Verdasco has seen a little too much of Diego Schwartzman. On Sunday in Rio de Janeiro, the two players met in the final of the 500-level clay court event, which Schwartzman won in straight sets. Both players immediately headed for the hard court tournament in Acapulco, where they drew each other in the first round. Verdasco lost again, this time winning six games instead of five.

The odds of this sort of final-to-first-round scenario, with back-to-back matches against the same opponent, is quite rare, and the surface switch makes this one even more unlikely. For one thing, the tour doesn’t move from one court type to another very frequently, and when they do, players don’t always travel through the same sequence of events. Another cause of improbability is that a pair of players who contest a final are usually pretty good, meaning that both of them are often seeded at their next event, making a first-round meeting impossible. In order to see a pair of consecutive matches like Schwartzman’s and Verdasco’s, we require synchronized schedules and a hefty helping of luck.

As Carl Bialik pointed out, this isn’t the first time Verdasco has played back-to-back matches in February against the same opponent, albeit on the same surface: He did so in 2011, dropping the San Jose final and then a Memphis first-rounder to Milos Raonic. Remarkably, when we broaden the search a bit, Verdasco’s name comes up twice more. In 2009, he lost to Radek Stepanek in the Brisbane final, then in his next event, the Australian Open, he beat Stepanek in the third round. (Radek played Sydney in the meantime, for what it’s worth.) And five years later, Verdasco overcame Nicolas Almagro to win the 2014 Houston title, then faced his countryman in his next event two weeks later, losing to Almagro in the round of 16. (Again, while they were back-to-back tourneys for Verdasco, Nico squeezed in a few matches in Monte Carlo in between.)

Back to the matter at hand: In the course of five decades of Open Era men’s tennis, just about everything has happened at least once before. But this exact scenario–two guys facing each other in a final, then a first round match the very next week on a different surface–is a new one. Relax any one of those constraints, and we see a few instances in the past.

Since 1970, there have been about 3,750 tour-level finals. Roughly one-third of the time, the two finalists ended up playing each other at least once more over the course of the season. 197 of those pairs drew each other in their very next event, and in another 62 of the finals, one of the players faced the other in his next tournament (though the other had played an event or two in the meantime, like Almagro and Stepanek). Several of the 197 duos played each other the next week, though it is a bit more common that there was a week off in between.

Of the 197 finalist pairs, 25 of them drew each other in the round of 32 or earlier in their following tournament, though not all of those were first-round matches. (Or, in the case of Andy Murray and Philipp Kohlschreiber in 2015 after contesting the Munich final, they played in Murray’s first Madrid match the following week but not Kohlschreiber’s, since Murray had a bye.) The most common round in which finalists met again was another final, which ensued about one-third of the time.

Dividing up the 197 pairs a different way, about one-fifth (39) played the follow-up match on a different surface. In only a few of these instances were the two surfaces hard and clay; a disproportionate number of these back-to-back matches happened in the 1970s and early 1980s, when carpet was regular feature on tour, so the hard-to-carpet or carpet-to-hard transition shows up in these results much more frequently than hard-to-clay or clay-to-hard. For any pair of surfaces in these 39 matches, only three occured in the round of 32, and none in the round of 64 or 128.

The three precedents for Schwartzman’s back-to-back wins all have several things in common. First, like Diego’s feat, the same player won both matches. The other two are unlike the Schwartzman double: In each case, there was a one-week break between the tournaments and one of the events was played on carpet.

The first similar achievement was recorded by Tom Gorman, who won consecutive matches against Bob Carmichael in 1976. The first was the Sacramento final (on carpet), followed by the first round in Las Vegas (on hard). Next up was Martin Jaite‘s pair of wins over Javier Sanchez in 1989. After triumphing in the Sao Paulo final (on carpet), Jaite won a hard-court first-rounder against the same opponent two weeks later. Finally, Fernando Gonzalez defeated Jose Acususo twice in a row in 2002, first in the clay-court final in Palermo, then a bit more than a week later on carpet in the first round in Lyon.

Like Schwartzman and his three closest predecessors, most of the finalists managed to defend their victory. Of the different-surface instances, the same player won both matches 26 of 39 times. When the two matches took place on the same surface, the title winner won the next match 101 of 158 times. Most recently, Yuichi Sugita failed to do so: After beating Adrian Mannarino for his first tour-level title in Antalya last summer, he met the Frenchman again in the Wimbledon second round and lost. In a more notable exception, Andre Agassi knocked out Petr Korda for the 1991 Washington title, then lost to Korda in his first match the next week in Montreal. (It wasn’t Korda’s first match, as he didn’t get a bye like Agassi did, but the extra effort paid off. The Czech reached the final.)

We could wait fifty years for an exact parallel of Schwartzman’s feat. Or we could set the bar a little lower and see a rematch almost immediately: Another of last week’s finalist pairs, Lucas Pouille and Karen Khachanov, followed up their Marseille title match with another meeting in the Dubai second round only three days later. Regardless of which standard you choose, there’s one person who would surely prefer to take a break from consecutive matches against the same opponent, and that’s Fernando Verdasco.

First Meetings in Grand Slam Finals

Italian translation at settesei.it

The 2017 Roland Garros final is crammed with firsts for 20-year-old Latvian Jelena Ostapenko. Playing in only her eighth major, she had never before reached the round of 16, let alone the final two. Her opponent, Simona Halep, has been here before–she lost the 2014 French Open final to Maria Sharapova–but the two women have one first in common: Halep and Ostapenko have never played each other.

Slam finals are usually reserved for an elite group, and that select few tends to play each other quite a bit. Since 1980, women’s major finalists have had an average of 12 previous meetings. The veteran Australian Open finalists this year, Serena Williams and Venus Williams, had faced off 27 times before their clash in Melbourne.

That makes the Halep-Ostapenko debut meeting an unusual one, but the situation is not unheard of. The 2012 Roland Garros final was the first match between Sharapova and Sara Errani (they’ve since played five more). Overall, there have been five first meetings in women’s major finals in the last 35 years:

Slam     Winner           Finalist               
2012 RG  Maria Sharapova  Sara Errani         
2009 US  Kim Clijsters    Caroline Wozniacki  
2007 W   Venus Williams   Marion Bartoli      
1988 RG  Steffi Graf      Natalia Zvereva

(There were probably a few more before that, but my database is missing a lot of matches from the mid-1970s, so I don’t know for sure.)

In all of these cases, the established star defeated the upstart, which bodes well for Halep. On the other hand, the Romanian doesn’t quite measure up to the previous four winners, all of whom had won a Grand Slam title before their final on this list.

First meetings in Grand Slam finals are a bit more common in the men’s game, though it’s been nearly a decade since the last one. We’ll probably wait quite a bit longer, too. Rafael Nadal and Stanislas Wawrinka will play for the 19th time on Sunday, and of the 45 possible pairings in the current top ten, only Kei Nishikori and Alexander Zverev have yet to face off. The next highest-ranked pair without a head-to-head is Andy Murray and Jack Sock which, come to think of it, would make for an interesting Wimbledon final next month.

The last debut clash on such a big stage was the 2008 Australian Open, between Novak Djokovic and Jo Wilfried Tsonga. It was the eighth in the last 35 years:

Slam     Winner            Finalist                
2008 AO  Novak Djokovic    Jo Wilfried Tsonga   
2003 US  Andy Roddick      Juan Carlos Ferrero  
1997 RG  Gustavo Kuerten   Sergi Bruguera       
1997 AO  Pete Sampras      Carlos Moya          
1996 W   Richard Krajicek  Malivai Washington   
1986 RG  Ivan Lendl        Mikael Pernfors      
1985 W   Boris Becker      Kevin Curren         
1984 AO  Mats Wilander     Kevin Curren

Before 1982, most first-meeting finals took place at the Australian Open, which at that time usually featured a weaker draw than the other Slams. For instance, the 1979 final was played by Guillermo Vilas and John Sadri. While Vilas is among the all-time greats, Sadri never advanced beyond the fourth round of any other major–where he might have encountered Vilas more often.

One thing seems certain: It won’t be the last meeting for Halep and Ostapenko. All of the pairs I’ve listed played at least once after their Slam final, and with the exception of Wilander-Curren, each one played at least twice more. Halep is only 25, so if she remains near the top of the game and Ostapenko continues climbing the ranks, the pair could aim to match Graf and Zvereva, who met 20 more times after the 1988 French Open final. The loser of today’s match will want to avoid Zvereva’s fate, though: In those 20 matches, the Belarussian won only once.

Dominic Thiem and Reversible Blowouts

Italian translation at settesei.it

A few weeks ago in Rome, Dominic Thiem got destroyed by Novak Djokovic, 6-1 6-0. It was a letdown after Thiem’s previous-round upset of Rafael Nadal, and it seemed to provide a reminder of the old adage that tennis is about matchups. Even someone good enough to beat the King of Clay might struggle against a different sort of opponent.

Those struggles didn’t last. On Wednesday, Thiem faced Djokovic again, this time in the French Open quarterfinals, and won in straight sets. In less than three weeks, the Austrian bounced back from a brutal loss to defeat one of the greatest players of all time.

I’ve written before about the limited value of head-to-head records: When the head-to-head suggests that one player will win but the rankings disagree, the rankings prove to be the better forecaster. More sophisticated rating systems such as Elo would presumably do better still, though I haven’t done that exact test. There are certainly individual cases in which something specific about a matchup casts doubt on the predictiveness of the rankings, but if you have to pick one or the other, head-to-heads are the loser.

What about blowouts? Going into Wednesday’s quarterfinal, my surface-specific Elo ratings suggested that Thiem had a 26% chance of scoring the upset. The recent 6-1 6-0 loss was factored into those numbers, but only as a loss–there’s no consideration of severity. Should we have been even more skeptical of Thiem’s chances, given the most recent head-to-head result?

As it turns out, Thiem is far from the first player to turn things around after such a nasty scoreline. The most famous example is Robin Soderling, who lost 6-1 6-0 to Nadal in Rome in 2009, then bounced back to register one of the biggest upsets in tennis history, knocking out Rafa at Roland Garros. Few recoveries are so dramatic, but there are hundreds more.

Most players who lose lopsided scorelines–for today’s purposes, I’m considering any match in which the loser won two games or fewer–never get a chance to redeem themselves. I found roughly 2250 such matches in the ATP’s modern era, and the same two players met again less than half of those times. The fact that the head-to-head continues is a signal itself: Mediocre players–the ones you’d expect to lose badly–don’t get another chance. Even some top-20 players rarely meet each other on court, so the sort of player who earns the chance for redemption might have already proven that his lopsided loss was just an off day.

Of the 951 occasions that a player loses badly and faces the same opponent again, he gets revenge and wins the next match 277 times–about 29%. Crazy as it sounds, if the only thing we knew about Djokovic and Thiem entering Wednesday’s match was that Djokovic had won the last match 6-1 6-0, our base forecast would’ve been pretty close to the 26% that the much-more sophisticated Elo algorithm offered us.

29% is much higher than I expected, but it is lower than the typical rate for players in this situation. I found all head-to-heads of at least two meetings, and for every match after the first, counted whether it maintained or reversed the previous result. In addition to isolating lopsided scores, I also considered matches in which the loser won a set, on the assumption that those might be tighter matchups. Finally, for each of those categories, I tracked whether the follow-up matches were on the same surface as the previous one. Here are the results, with all win percentages shown from the perspective of the player who, like Thiem, lost the first encounter:

Score     Next Surface  Matches   Wins  Win %  
Any loss  All             68128  26586  39.0%  
Any loss  Same            31084  11855  38.1%  
Any loss  Diff            37044  14731  39.8%  
Bad loss  All               951    277  29.1%  
Bad loss  Same              457    128  28.0%  
Bad loss  Diff              494    149  30.2%  
Won set   All             26075  11286  43.3%  
Won set   Same            11766   4974  42.3%  
Won set   Diff            14309   6312  44.1%

The chances of recovering from a bad loss are better than I thought, but they are considerably worse than the odds that a player reverses the result after a less conspicuous scoreline–39%. The table also shows that the player seeking revenge is more likely to get it if the opportunity arises on a different surface, though not by a wide margin.

It’s clear that players are less likely to recover from a bad loss than from a more typical one, but how much of that is selection bias? After all, most of the players who lose 6-1 6-0 aren’t of the caliber of Thiem or Soderling, even if they are good enough to stick around in main draws and ultimately face the same opponent again.

To answer that question, I looked again at those 950 post-blowout matches, this time with pre-match Elo ratings. After eliminating everything before 1980 and a few other matchups with very little data, we were left with just under 600 data points. In this subset, Elo predicted that the players who lost badly had a 33.6% chance of winning the follow-up match. As we’ve seen, the actual success rate was 29%. Players who won lopsided matches outperformed their Elo forecast in the next meeting.

It’s not a huge difference, but enough to suggest that the matchup tells a little bit about how the next contest will go. One match can make a difference in the forecast–as long as it isn’t against Dominic Thiem.

—

Digging into the cases when a player lost badly and then recovered, I found a couple of entertaining examples:

Former No. 7 Harold Solomon beat Ivan Lendl in their first meeting, 6-1 6-1. Later that year, they met again at the US Open, and Lendl won, 6-1 6-0 6-0. Lendl also won their six matches after that.
Over the course of four years, Phil Dent and Mark Cox played three lopsided matches against each other. Cox won the first, Dent got revenge in the second, and Cox reversed things again in the third.

Roger Federer’s Impressive but Not-Entirely-Relevant Dominance of the Istanbul Field

Roger Federer has faced 14 of the 27 other players in this week’s Istanbul field, and owns a career record of 59-1 against them. His one loss came to Jurgen Melzer, while more than half of his win total is thanks to his decade-long dominance of Mikhail Youzhny (16-0) and Jarkko Nieminen (14-0).

It’s rare that players of Federer’s stature contest such small events, so we don’t expect to see such lopsided head-to-heads very often. In fact, if we limit our view to events where a player faced at least 10 of the other entrants, it is only the 17th time since 1980 that someone has entered an event with a won-loss percentage of 95% or better against the field.

Federer himself represents two of the previous 16 times this has happened. The most notable of them is 2008 Estoril. He had previously faced 14 of the other players in the draw, and had never lost to any of them in 46 meetings. There are only four other instances of players undefeated against a field, all between 1980 and 1984 and in many fewer matches.

The most eye-grabbing of those early-80s accomplishments was Ivan Lendl‘s record entering the 1980 Taipei event. He had faced 15 of the men in the draw, posting a record of 24-0 up to that point. Lendl’s name is the most common on the list, having entered tournaments with a 95% won-loss record against the field on four different occasions, highlighted by a 79-4 mark against the other competitors at Stratton Mountain in 1988.

Federer won the 2008 title in Estoril and Lendl claimed the 1980 trophy in Taipei, but Lendl was ousted in the second round of the 1988 Stratton Mountain event. Federer has also demonstrated that a stratospheric record against the field is no guarantee of success.

After Estoril, Roger’s second-best record entering an event was in Gstaad in 2013. He held a 73-3 record against the field, with each of the three losses coming against different opponents. He lost his opening-round match in straight sets to Daniel Brands. His record against the field of the previous week’s Hamburg event was nearly perfect as well at 137-8, but Federico Delbonis stopped him in the semifinals there.

Rafael Nadal can tell a similar story. His best record against a field was in Santiago two years ago, coming back from injury. He had lost only 1 of 28 career matches against the other players in the draw. That week, Horacio Zeballos doubled Rafa’s loss count.

In fact, of the 16 times that a player went into an event with a 95% or better record against the field, the favorite won only six of them. Expanding the sample to records of 90% or better, the dominant player won 30 of 72 titles. Neither mark is as good as we’d expect if the historically great players continued to win matches at a 95% or 90% clip. In practice, head-to-head records just aren’t as predictive as they seem to be.

As is evident from some of the examples I’ve given, there are mitigating circumstances for many of these losses, and they aren’t entirely random. These days, when a player enters an event that seems below him, there’s a reason for it. Nadal rarely plays 250s; he was doing so to work his way back into match form. Federer rarely seeks out smaller events on clay; he was experimenting with a new racket.

This week, there’s no reason why Fed shouldn’t perform at his usual level–at least his usual level for clay–and win the four matches he needs to claim yet another title. But if he suffers his second loss against the players gathered in Istanbul this week, it won’t be quite as much of a shock as that 59-1 record implies.