Second-Strike Tennis: When Returners Dominate

On Wednesday, Diego Schwartzman scored a notable upset, knocking out 12th seed Roberto Bautista Agut in the second round of the Monte Carlo Masters. Even more unusual than Bautista Agut’s first-round exit was the way it happened. Both players won more than half of their return points: 61% for Schwartzman and 52% for Bautista Agut. There were 14 breaks of serve in 21 games.

Players like Schwartzman win more than half of return points fairly regularly. In the last 12 months, including both Challenger and tour-level matches, the Argentine–nicknamed El Peque for his diminutive stature–has done so more than 20 times. What is almost unheard of in the men’s game is for both players to return so well (or serve so poorly) that neither player wins at least half of his service points.

Since 1991–the first year for which ATP match stats are available–there have been fewer than 70 matches in which both players win more than half of their return points. (There are another 25 or so in which one player exceeded 50% and the other hit 50% exactly.) What’s more, these matches have become even less frequent over time: Wednesday’s result was the first instance on the ATP tour since 2014, and there have been fewer than 30 since 2000.

Here are the last 15 such matches, along with the both the winner’s (W RPW) and loser’s (L RPW) rates of return points won. Few of the players or surfaces come as a surprise:

Year  Event            Players                 W RPW  L RPW  
2017  Monte Carlo      Schwartzman d. RBA      61.4%  51.9%  
2014  Rio de Janeiro   Fognini d. Bedene       50.6%  50.6%  
2014  Houston          Hewitt d. Polansky      51.3%  51.5%  
2014  Estoril          Berlocq d. Berdych      51.5%  50.6%  
2013  Monte Carlo      Bautista Agut d. Simon  58.8%  50.6%  
2013  Estoril          Goffin d. P Sousa       55.2%  50.5%  
2011  Casablanca       Fognini d. Kavcic       51.0%  51.9%  
2011  Belgrade         Granollers d. Troicki   61.5%  50.8%  
2008  Barcelona        Chela d. Garcia Lopez   54.3%  50.5%  
2008  Costa Do Sauipe  Coria d. Aldi           58.5%  51.9%  
2007  Rome Masters     Ferrero d. Hrbaty       52.9%  51.7%  
2007  Hamburg          Ferrer d. Bjorkman      50.6%  50.6%  
2006  Monte Carlo      Coria d. Kiefer         53.2%  50.9%  
2006  Hamburg Masters  Gaudio d. A Martin      57.3%  51.1%  
2006  Australian Open  Coria d. Hanescu        53.4%  50.6%

All but 8 of the 69 total matches were on clay. One of the exceptions is at the bottom of this list, from the 2006 Australian Open, and before 2006, there were another five hard-court contests, along with two on grass courts. (The ATP database isn’t completely reliable, but in each of these cases, the high rate of return points won is partially verified by a similarly high number of reported breaks of serve.)

Bautista Agut, who won one of these matches four years ago in Monte Carlo, is one of several players who participated in multiple return-dominated clashes. Guillermo Coria played in five, winning four, and Fabrice Santoro took part in four, winning three. Coria won more than half of his return points in 75 tour-level matches over the course of his career.

Over course, both Schwartzman and Baustista Agut cleared the 50% bar with plenty of room to spare. The Spaniard won 51.9% of return points and Schwartzman comfortably exceeded 60%, putting them in an even more elite category. It was only the 22nd match since 1991 in which both players won at least 51.9% of return points.

As rare as these matches are, Schwartzman is doing everything he can to add to the list. With a ranking now in the top 40, he has entered just about every clay tournament on the schedule, so the most return-oriented competitor in the game is going to play a lot more top-level matches on slow surfaces. If anyone has a chance at equaling Coria’s mark of winning four of these return-dominated matches, my money’s on El Peque.

Playing Even Better Than Number One

Last night in Miami, Venus Williams beat newly re-minted WTA No. 1 Angelique Kerber. Venus, of course, has plenty of experience clashing with the very best in women’s tennis, with 15 Grand Slam finals and three spells at the No. 1 ranking herself.

Last night’s quarterfinal was Venus’s 37th match against a WTA No. 1  and her 15th win. Kerber became the sixth different top-ranked player to lose at the hands of the elder Williams sister.

All of these numbers are very impressive, especially when you consider that, taken as a whole, WTA No. 1s have won just over 88% of their nearly 2,300 matches since the modern ranking system was instituted. However, Venus doesn’t hold the record in any of these categories.

Records against No. 1s are a somewhat odd classification, since the best players tend to reach the top spot themselves. For example, Martina Hingis played only 11 matches against top-ranked opponents, barely one-fifth as many as the leader in that category. On the other hand, injuries and other layoffs have meant that many all-time greats have found themselves lower in the rankings for long stretches. That is particularly true of Venus and Serena Williams.

With her 37 matches played against No. 1s, Venus is approaching the top of the list, but it will take a superhuman effort to catch Arantxa Sanchez Vicario, at 51:

Rank  Player                   Matches vs No. 1
1     Arantxa Sanchez Vicario                51
2     Gabriela Sabatini                      38
3     Venus Williams                         37
4     Lindsay Davenport                      34
5     Conchita Martinez                      33
6     Helena Sukova                          31
7     Serena Williams                        28
8     Svetlana Kuznetsova                    27
-     Jana Novotna                           27
10    Amelie Mauresmo                        25
11    Maria Sharapova                        23

Wins against No. 1s is a more achievable goal. Martina Navratilova holds the current record at 18*, followed by Serena at 16, and then Lindsay Davenport and Venus at 15:

Rank  Player               Wins  Losses
1     Martina Navratilova    18*      
2     Serena Williams        16      12
3     Lindsay Davenport      15      19
-     Venus Williams         15      22
5     Steffi Graf            11       8
6     Gabriela Sabatini      10      28
7     Amelie Mauresmo         8      17
8     Svetlana Kuznetsova     7      20
-     Maria Sharapova         7      16
-     Mary Pierce             7      15
-     Justine Henin           7       9

*My database does not have rankings throughout Navratilova’s entire career, but other sources credit her with 18 wins.

Win percentage against top-ranked opponents is a bit trickier, as it depends where you set the minimum number of matches. I’ve drawn the line at five. That’s rather low, but I wanted to include Alize Cornet and Elina Svitolina, active players who have each won three of their six matches against No. 1s. By this standard, Venus ranks eighth, though equally reasonable thresholds of 8 or 10 matches would move her up two or three places:

Rank  Player             Wins  Losses   Win%
1     Steffi Graf          11       8  57.9%
2     Serena Williams      16      12  57.1%
3     Petra Kvitova         5       4  55.6%
4     Elina Svitolina       3       3  50.0%
-     Alize Cornet          3       3  50.0%
6     Lindsay Davenport    15      19  44.1%
7     Justine Henin         7       9  43.8%
8     Venus Williams       15      22  40.5%
9     Vera Zvonareva        4       7  36.4%
-     Dinara Safina         4       7  36.4%

Remember that the average player wins fewer than 12% of matches against No. 1s!

Finally, Venus’s defeat of Kerber gave her a win against her sixth different No. 1, moving her into second place in that department. As is so often the case, she trails only her sister, who has beaten seven. Oddly enough, there is very little overlap between Serena’s and Venus’s lists: Their only common victims are Hingis and Davenport. The full list:

Rank  Player               No. 1s defeated
1     Serena Williams                    7
2     Venus Williams                     6
3     Steffi Graf                        5
-     Kim Clijsters                      5
-     Amelie Mauresmo                    5
-     Maria Sharapova                    5
7     Petra Kvitova                      4
-     Lindsay Davenport                  4
-     Justine Henin                      4
-     Svetlana Kuznetsova                4

If Karolina Pliskova–who now stands within 1500 points of No. 1 and could further close the gap in Miami–reaches the top spot, Venus may get a chance to beat a 7th top player. Of course, Serena could get that chance, as well.

Best of Five and Marin Cilic’s Improbable Collapse

Leading up to the final two rubbers of this year’s Davis Cup final in Croatia, the hosts were heavily favored. They held a 2-1 advantage, and both of the remaining singles matches would pit a Croatian against a lower-ranked Argentine. To win the Cup, they only needed to win one of those matches.

When Marin Cilic built a two-set lead over Juan Martin del Potro, Croatian fans could be forgiven for thinking it was in the bag. Instead, Delpo fought back to win in five sets, and Federico Delbonis upset a flat Ivo Karlovic to seal Argentina’s first-ever Davis Cup title. Some people will point to the Cilic-Delpo match time of 4:53 as another reason to switch to best-of-three. The rest of us will see it as yet another reminder of why best-of-five must retain its role on tennis’s biggest stages.

In a best-of-three format, Cilic would’ve claimed the Cup for Croatia after two hours of play. Instead, he merely came very close. My Elo singles ratings gave Cilic a 36.3% chance of beating Delpo and Karlovic a 75.8% chance of defeating Delbonis. Taken together, that’s a likelihood of 84.6% that Croatia would claim the trophy. After Cilic won the first two sets, his odds increased to about 81%, pushing Croatia’s chances over the 95% mark. In fourteen previous tries, del Potro had never recovered from an 0-2 deficit.

And then Argentina came back. Comebacks from two sets down tend to stick in our memory, so it’s easy to forget just how rare they are. Yesterday’s match was only the 28th such comeback in 2016. That’s out of a pool of 656 best-of-five contests, including 431 in which one player built a 2-0 lead. This year isn’t unusual: Going back to 2000, the number of wins from a 0-2 deficit has never exceeded 32.

Comebacks from 0-2 are even rarer in Davis Cup. At the World Group level this year, including play-offs, Delpo was the 61st player to fall into a 0-2 hole, but he was only the second to recover and win the match. The other was Jack Sock, whose July comeback (over Cilic–more on that in a bit) wasn’t enough to move his USA squad into the semifinals. Since 2000, 5.8% of 2-0 leads turn into comeback victories, but only 4.3% of World Group 2-0 leads do the same.

Cilic’s season has defied the numbers. In addition to his 2-0 collapses against Sock and del Potro, he held a 2-0 advantage before losing to Roger Federer in the Wimbledon quarterfinals. His 2016 is only the third time in ATP history that a player lost three or more matches after winning the first two sets. The previous two–Viktor Troicki’s 2015 season and Jan Siemerink’s 1997–are unlikely to make Cilic feel any better.

Still, even Cilic’s record indicates the rarity of victories from an 0-2 disadvantage. Before the Wimbledon quarterfinal, the Croatian had never lost a match after taking the first two sets, for a record of 60-0. Even now, his Davis Cup record after going up two sets to love is a respectable 11-2. His overall career mark of 95.7% (66-3) is better than average.

Unless Cilic crumbles under certain spotlights (but not others, as evidenced by his five-set win over Delbonis on Friday), his series of unfortunate collapses may just be a fluke. In addition to that 60-0 streak, he has never had a problem converting one-set leads in best-of-three matches. This year, he won 29 out of 33 best-of-threes after winning the first set, an above-average rate of 88%. (And one of the losses was against Dominic Thiem, so he never had a chance.)

The longer the match format, the more likely that the better player emerges triumphant. That’s why there are fewer upsets in best-of-five than in best-of-three, and why tiebreaks are often little better than flips of a coin. Usually that works in favor of a top-tenner such as Cilic: In most matchups he is the superior player. But in two of his three collapses this season, he’s fallen victim to a favorite who uses the longer format to overcome an early run of poor form.

The debate over best-of-five will surely continue, despite this weekend’s Davis Cup tie adding another unforgettable five-set epic to an already long list. But after Delpo’s performance yesterday, you’ll have a harder time finding someone to campaign for shorter matches–especially in Argentina.

Andy Murray and the Longest Break-Per-Match Streaks

Among Andy Murray‘s many accomplishments in 2016, he achieved an impressive–though obscure–feat. In each one of his 87 matches, he broke serve at least once. He has broken at least once per match since failing to do so against Roger Federer in the 2015 Cincinnati semifinals, for an active streak of 107 matches.

Where does that place him among the greats of men’s tennis? Just how unusual is it to break serve in every match for an entire season? As is the case with too many tennis statistics, we don’t know. Someone finds an impressive-sounding stat, and that’s the end of the story. We can’t always fix that, but in this case, we can add some context to Murray’s accomplishment.

Full break-per-match seasons

I’ve collected break stats for matches back to 1991, though we need to keep in mind that there are some mistakes in the 1990s data. Further, Davis Cup presents a problem, as it is excluded entirely. Sometimes we can tell from the scoreline that a player broke serve–as with all of Murray’s Davis Cup matches this year–but often we cannot. I’ll have more to say about that in specific cases below.

Since 1991, there have been at least 14, and perhaps as many as 20 instances in which a player broke serve in every match of a season. (Minimum 40 tour-level matches, and I’ve excluded retirements when calculating both minimums and the streaks themselves.) I say “instances” because several players–Andre Agassi, Lleyton Hewitt, Rafael Nadal, and Nikolay Davydenko–pulled it off more than once. Hewitt’s 2001 season had the most matches–95–of any of them, followed by Murray’s 2016 and Nadal’s 2005, at 87 each.

Here is the complete list:

Player                  Season  Matches  (Unsure)  
Andy Murray               2016       87         0  
Juan Monaco               2014       41         0  
Novak Djokovic            2013       83         0  
Rafael Nadal              2010       79         0  
Nikolay Davydenko         2008       73         0  
Nikolay Davydenko         2007       82         0  
Lleyton Hewitt            2006       46         0  
Rafael Nadal              2005       87         0  
David Nalbandian          2005       63         0  
Andre Agassi              2003       55         0  
Lleyton Hewitt            2001       95         0  
Lleyton Hewitt            2000       76         1  
Hernan Gumy               1997       53         1  
Alex Corretja             1997       67         0  
Andre Agassi              1995       81         0  
Magnus Gustafsson         1994       40         0  
Carlos Costa              1992       60         0  
Guillermo Perez Roldan    1991       40         2  
Ivan Lendl                1991       72         0  
Boris Becker              1991       61         2

(The “Unsure” column indicates how many matches are missing stats and may not have included a break of serve.)

Several more players came close. Federer broke serve in all but one match in three separate seasons. Agassi, Novak Djokovic, David Ferrer, and Thomas Muster all did so twice.

We shouldn’t be surprised that so many players–especially the greats–have broken so often. It’s very rare to win a match without breaking serve: Of the 2,570 ATP tour-level matches from this season for which I have match stats, the winner broke serve in all but 30 of them. Even losers break serve in more than two out of every three matches: In 2016, the loser broke serve in 1,843 of the 2,570 matches, 72% of the time.

Still, there are enough dominant servers on tour that it is difficult to last an entire season without being shut out of the break column. In 1995, Muster broke serve in 99 matches, but failed to do so when he drew the big-serving (and completely unheralded) qualifier TJ Middleton on the carpet in St. Petersburg. Murray’s current streak is all the more impressive because, in his 107 matches, he has faced Milos Raonic six times, John Isner four times, Kevin Anderson and Nick Kyrgios twice each, and Ivo Karlovic once. Given the chance, he probably would’ve broken TJ Middleton as well.

Break-per-match streaks

For Murray to surpass the longest streaks in this category, it will take several more months of high-quality returning. As we saw above, Davydenko and Hewitt may have gone two full years breaking serve in every match they played. In both cases, the lack of ITF data makes their records unclear, but regardless of those details, Davydenko has set an extremely high bar.

Here are all the break-per-match streaks of 100 or more matches since 2000:

Player             Start   End  Streak  Possible  
Nikolay Davydenko   2006  2009     159       182  
Rafael Nadal        2004  2006     156            
Rafael Nadal        2009  2011     146            
Andre Agassi        2002  2004     143            
Novak Djokovic      2012  2014     127            
Lleyton Hewitt      1999  2002     124       230  
Andy Murray         2015  2016     107         ∞  
David Nalbandian    2004  2006     104

This season, Murray didn’t play his 53rd match until August at the Olympics; he’ll need to break serve at least once in that many matches to reach the top of this list.

The exact length of Davydenko’s streak hinges on his 2008 Davis Cup semifinal match against Juan Martin del Potro, which he lost in straight sets. If he broke serve in that match, his streak stretched into early 2009, spanning 182 matches.

(Edit: Thanks to Andrew Moss, we now know that Davydenko did break serve in that match, according to this contemporaneous report.)

Hewitt’s best streak is even more unclear. I don’t have break stats for his 6-3 6-3 loss to Max Mirnyi at the 2000 Olympics. If he didn’t break Mirnyi–a definite possibility, given The Beast’s serving prowess–the streak is “only” 124 matches. If he did, the streak is at least 187, and the exact length depends on more unknowns, including both of his singles matches in the 1999 Davis Cup final against France.

(Edit #2! Thanks to Carl, we know that Hewitt broke Mirnyi, so his streak is at least 187 matches. The next issue is his last match of the 1999 season, a dead rubber against Sebastian Grosjean in that year’s Davis Cup final. Hewitt lost 6-4 6-3, but Grosjean was hardly an overpowering server. Hewitt lost his previous Davis Cup match in straight sets as well, a live rubber against Cedric Pioline, and a match report establishes that Hewitt broke serve. If he broke Grosjean, the streak stretches back to April 1999, and numbers the full 230 matches.)

In any case, Murray has already earned himself a place among the greatest returners in modern tennis. In 2017, we’ll see just how far he can climb this list.

Factchecking the History of the ATP Number One With Elo

As I wrote at The Economist this week, Andy Murray might sit atop the ATP rankings, but he probably isn’t the best player in tennis right now. That honor still belongs to Novak Djokovic, who comes in higher on the Elo ranking list, which uses an algorithm that is more predictive of match outcomes than the ATP table.

This isn’t the first time Elo has disagreed with the official rankings over the name at the top. Of the 26 men to have reached the ATP number one ranking, only 18 also became number one on the Elo list. A 19th player, Guillermo Coria, was briefly Elo #1 despite never achieving the same feat on the ATP rankings.

Four of the remaining eight players–Murray, Patrick Rafter, Marcelo Rios, and John Newcombe–climbed as high as #2 in the Elo rankings, while the last four–Thomas Muster, Carlos Moya, Marat Safin, and Yevgeny Kafelnikov–only got as high as #3. Moya and Kafelnikov are extreme cases of the rankings mismatch, as neither player spent even a single full season inside the Elo top five.

By any measure, though, Murray has spent a lot of time close to the top spot. What makes his current ascent to the #1 spot so odd is that in the past, Elo thought he was much closer. Despite his outstanding play over the last several months, there is still a 100-point Elo gap between him and Djokovic. That’s a lot of space: Most of the field at the WTA Finals in Singapore this year was within a little more than a 100-point range.

January 2010 was the Brit’s best shot. At the end of 2009, Murray, Djokovic, and Roger Federer were tightly packed at the top of the Elo leaderboard. In December, Murray was #3, but he trailed Fed–and the #1 position–by only 25 points. In January, Novak took over the top spot, and Murray closed to within 16 points–a small enough margin that one big upset could make the difference. Altogether, Murray has spent 63 weeks within 100 points of the Elo top spot, none of those since August 2013.

For most of the intervening three-plus years, Djokovic has been steadily setting himself apart from the pack. He reached his career Elo peak in April of this season, opening up a lead of almost 200 points over Federer, who was then #2, and 250 points over Murray. Since Roland Garros, Murray has closed the gap somewhat, but his lack of opportunities against highly-rated players has slowed his climb.

If Murray defeats Djokovic in the final this week in London, it will make the debate more interesting, not to mention secure the year-end ATP #1 ranking for the Brit. But it won’t affect the Elo standings. When two players have such lengthy track records, one match doesn’t come close to eliminating a 100-point gap. Novak will end the season as Elo #1, and he is well-positioned to maintain that position well into 2017.

Dominic Thiem and the Best Deciding-Sets Seasons in ATP History

Yesterday at the ATP World Tour Finals, Dominic Thiem won a three-set match against Gael Monfils, his 22nd deciding-set victory of 2016. Despite losing to Novak Djokovic in three sets on Sunday, Thiem is enjoying one of the best deciding-set seasons in ATP history.

The loss to Djokovic was only Thiem’s third in 25 deciding sets this year. He began the season with 14 consecutive deciding-set wins, including back-to-back third-set tiebreaks in Buenos Aires against Rafael Nadal and Nicolas Almagro. He strung together another seven straight between May and September, including a grass-court upset of Roger Federer in Stuttgart.

Among players who contested at least 20 deciding sets in a season, Thiem’s winning percentage of 88% is the fifth-best record in the ATP’s modern era. Not every player reaches the 20-decider threshold–some, like Djokovic, avoid it by winning most of their matches in straight sets–but it’s no statistical oddity. There have been nearly 1,000 player-seasons with at least 20 deciders since the 1970s, including Andy Murray’s 17-6 record in 2016.

Outstanding single-season deciding-set records don’t guarantee long-term success. Thiem appears on this list amid a mix of famous and lesser-known names, from Federer to Onny Parun:

Player           Year  Deciders  Wins  Win Perc  
Mario Ancic      2006        24    22     91.7%  
Ilie Nastase     1971        23    21     91.3%  
Tom Okker        1974        20    18     90.0%  
Roger Federer    2006        20    18     90.0%  
Dominic Thiem    2016        25    22     88.0%  
Kei Nishikori    2014        24    21     87.5%  
Stan Smith       1972        22    19     86.4%  
Joakim Nystrom   1984        22    19     86.4%  
Guillermo Vilas  1977        29    25     86.2%  
Onny Parun       1975        34    29     85.3%

Parun’s 1975 season is particularly notable, as no other player has won so many deciding sets in a single year. In 1996, Yevgeny Kafelnikov came close, winning 28. One gets the idea he was trying: He played 105 matches that year, 40 of which went the distance. In more recent years, big names have played more limited schedules, and Thiem is the only active player to win at least 22 deciding sets in a single season. Dmitry Tursunov gave it a shot in 2006, playing 37 deciders, but he won only 20.

Like so many tennis stats, this one can be fluky. For every Kei Nishikori–who has won an incredible 77% of deciding sets at tour level, including some record-setting streaks--there is a Grigor Dimitrov, who won 18 of 22 deciding sets in 2014, then barely broke even the following year, claiming only 11 of 21. Of the 27 players who have posted a 20-decider, 80% winning percentage season, not a single one managed an 80% winning percentage the following year.

For all of his talents, Thiem probably won’t follow in Nishikori’s footsteps. The Austrian won only half of his 40 deciding sets before this season. But a more modest record in these matches is hardly insurmountable. In 1996, Pete Sampras put together his best deciding-sets record, winning 83% of his 24 deciders. The following year, his record fell to a pedestrian 56%, which didn’t keep him from winning two Grand Slams and finishing the season at the top of the rankings.

If Thiem is to continue climbing the rankings, he’ll be better off taking Djokovic’s path, winning most of his deciding sets, but playing them much less frequently. In the last decade, Novak has played 20 deciding sets in a season only three times, and he has only gone the distance 10 times in 2016. Even Nishikori would have to agree: Djokovic’s method is working just fine.

Elina Svitolina and Multiple #1 Upsets

Last week in Beijing, Elina Svitolina beat new WTA #1 Angelique Kerber. It was the first time the Ukrainian defeated Kerber this season, but it wasn’t her first 2016 triumph over a player ranked #1. At the Rio Olympics in August, Svitolina upset then-top-ranked Serena Williams.

It’s unusual for a player to face two (or more) different #1-ranked opponents in the same season. Since 1985, it has happened 136 times on the WTA tour and 148 times on the ATP tour. That’s less than five times per season per tour.

Of course, it’s much less common to upset multiple #1-ranked opponents, as Svitolina did. This was only the 16th time a woman did so (again, since 1985), while it has happened on the men’s side 18 times.

Here is a full list of WTA player-seasons that featured defeats of more than one top-ranked player:

Year  Player               Upsets                      
2016  Elina Svitolina      Kerber; Serena              
2010  Samantha Stosur      Serena; Wozniacki           
2009  Venus Williams       Serena; Safina              
2008  Dinara Safina        Henin; Sharapova; Jankovic  
2006  Justine Henin        Davenport; Mauresmo         
2003  Justine Henin        Serena; Clijsters           
2002  Kim Clijsters        Serena; Venus               
2002  Serena Williams      Capriati; Venus             
2001  Lindsay Davenport    Capriati; Hingis            
1999  Amelie Mauresmo      Hingis; Davenport           
1999  Venus Williams       Davenport; Hingis           
1997  Amanda Coetzer       Hingis; Graf                
1996  Jana Novotna         Graf; Seles                 
1996  Kimiko Date Krumm    Graf; Seles                 
1991  Martina Navratilova  Graf; Seles                 
1991  Gabriela Sabatini    Graf; Seles

It’s quite an accomplished list. As we might expect, there’s a lot of overlap between the players who achieved these upsets and past and future #1-ranked players. The real standouts here are Justine Henin and Venus Williams, who managed the feat twice, and Dinara Safina, who faced three different #1s in 2008, going undefeated against them.

Here are the men who beat multiple #1s in the same season:

Year  Player                 Upsets             
2013  Juan Martin Del Potro  Nadal; Djokovic    
2012  Andy Murray            Federer; Djokovic  
2011  David Ferrer           Nadal; Djokovic    
2011  Jo Wilfried Tsonga     Nadal; Djokovic    
2010  Marcos Baghdatis       Nadal; Federer     
2009  Juan Martin Del Potro  Nadal; Federer     
2008  Andy Murray            Nadal; Federer     
2008  Gilles Simon           Nadal; Federer     
2003  Rainer Schuettler      Roddick; Agassi    
2003  Fernando Gonzalez      Hewitt; Agassi     
2001  Greg Rusedski          Safin; Kuerten     
2001  Max Mirnyi             Safin; Kuerten     
1995  Michael Chang          Agassi; Sampras    
1992  Richard Krajicek       Courier; Edberg    
1991  Guy Forget             Edberg; Becker     
1991  Andrei Cherkasov       Edberg; Becker     
1990  Boris Becker           Lendl; Edberg      
1988  Boris Becker           Wilander; Lendl

This list isn’t quite as impressive, though it does capture several very good players at their best.  It also highlights the world-beating potential of Max Mirnyi, who–despite never reaching the top 15 himself–finished the 2001 season with a 3-1 record against ATP #1s.

The rarity of facing multiple #1s in the same season–let alone beating them–stops us from drawing any meaningful conclusions about what Svitolina’s feat indicates for her future. At the very least, however, it reminds us of the Ukrainian’s potential as a future star, and puts her among some very good historical company.