In Search of Davis Cup Heroes

Come up big for one important weekend, and you can earn a reputation as a Davis Cup hero that lasts a lifetime.  We tend to remember big stories and crucial moments more than career-long trends, so images of Radek Stepanek holding last year’s trophy loom larger in memory than his mediocre-sounding 12-11 record in live singles rubbers.

This isn’t to say that Stepanek isn’t a Davis Cup hero.  Some matches are more important than others, and even 12-11 can be impressive when you consider that four of his 11 losses came against top-ten players.  And that’s to say nothing about doubles.

To find out who really performs under the scrutiny of Davis Cup crowds, we need to go deeper.  We must determine how many matches a player like Stepanek should’ve won, then compare his actual mark.  When we do that with two decades of Davis Cup results, we find some unsung stalwarts and some overrated superstars.  The international competition isn’t the endless source of upsets that pundits like to insist it is, but some players do provide us with more upsets than others.

Here’s how it works.  For every live Davis Cup rubber, we take each player’s ranking and estimate the likelihood that each player would win the match.  In the case of today’s match between Stepanek and Novak Djokovic, we might estimate that the Serbian has a 95% chance of winning.  Then we compare the results.  If Novak wins, he’ll outperform expectations by five percentage points (100% instead of 95%), while the Czech underperforms by the same amount (0% instead of 5%).

Do that for every match, tally the results for every player, and things start to get interesting.

Among active and recently-active players, there’s an unusual twosome near the top of the rankings: Juan Martin del Potro and David Nalbandian. (Delpo partisans will be glad to know that he just edges out his older compatriot.)  Del Potro has won 11 of 15 live rubbers, though based on his competition, we would only have expected him to win eight.  Four of those wins were over higher-ranked players.  Nalbandian is a stunning 23-6 in live singles rubbers (including 6-4 against higher-ranked players), while we would have expected him to win between 17 and 18.

Both Argentines have outperformed their rankings, winning between 32% (Nalbandian) and 36% (Delpo) more matches than we would expect.  Of those with at least ten live rubbers under their belts, the only active player to better those marks is Frank Dancevic.  The Canadian has won three live rubbers despite never facing a lower-ranked player in any of his ten matches.  3-7 may not seem awe-inspiring, but the numbers suggest he should have won only one match, with an outside shot at a second.  He has more than doubled that.

(I’m setting the standard here at 10 live rubbers. But it would be foolish to ignore Amir Weintraub, who has been historically great in his seven live rubbers.  Like Dancevic, he has never faced a lower-ranked player in Davis Cup, yet he has amassed a 4-3 record, despite an expectation of between one and two wins.)

How about the familiar faces this weekend?  Stepanek has racked up about 13% more Davis Cup singles wins than expected, while Tomas Berdych is slightly positive, at +4%.  Djokovic and his almost-teammate Janko Tipsarevic are a bit below expectations.  This isn’t really a knock on Novak, though.  When you’ve spent so many years close to top, expectations are very high.  Also, his two high-profile Davis Cup retirements–against Delpo in 2011 and against Nikolay Davydenko in 2008–count against him.  Take out those two matches, and his mark swings to a +4%, equal to Berdych.

In any event, no modest over- or underperformance is likely to swing the singles matches in this weekend’s tie.  Even a sluggish Djokovic would probably whip a hero-mode Stepanek.  Neither Novak or Berdych has displayed enough of a Davis Cup-specific tendency to alter the outcome of their match.  And Tipsarevic’s replacement, Dusan Lajovic, would need to channel his inner Dancevic to have any impact at all.

If hero-mode Stepanek is to alter the course of this tie, it will probably happen in the doubles rubber.  Unfortunately for Radek, I don’t have the numbers to disprove a strong suspicion that the most outrageous overperformance in Davis Cup this year belongs to Ilija Bozoljac, one of the men who will be standing across the net from him for–we can only hope–five sets tomorrow.

After the jump, I’ve included +/- numbers like those cited above for many top-ten and otherwise interesting players.

In the table below, ‘Lv’ is career live rubbers, ‘upW’ is upset wins–victories over higher-ranked players, ‘upL’ is upset losses–losses to lower-ranked players, ‘prdW’ is predicted/expected wins given the quality of competition, ‘actW’ is actual wins against all opponents, and ‘+/-‘ is the percentage by which the player has exceeded expectations–or not.  Some numbers might differ by one or two from official records because I excluded matches in which one player was unranked.

Player                 Lv  upW  upL  prdW  actW   +/-  
Juan Martin Del Potro  15    4    1   8.1    11   36%  
David Ferrer           21    2    2  15.0    18   20%  
Rafael Nadal           20    1    0  16.2    19   17%  
Radek Stepanek         23    4    3  10.6    12   13%  
Roger Federer          37    5    5  27.8    31   12%  
Lleyton Hewitt         40    5    6  27.0    30   11%  
Tomas Berdych          34    4    3  21.2    22    4%  
Jo Wilfried Tsonga     14    0    2  11.3    11   -3%  
Janko Tipsarevic       20    2    3  11.5    11   -5%  
Novak Djokovic         21    0    3  17.0    16   -6%  
Richard Gasquet        12    0    3   8.0     7  -12%  
Stanislas Wawrinka     22    1    2  12.9    11  -15%  
John Isner             11    2    4   5.1     4  -21%  
James Blake            18    1    7  11.0     7  -36%  
Thomaz Bellucci        13    1    2   6.3     4  -37%

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