Sizing Up Surprising Head-to-Heads

Why is it that some players seem to consistently underperform against certain opponents? And how could we measure the all-time most surprising head-to-heads in the game?

In just three weeks, 19 year-old Greek phenom Stefanos Tsitsipas has won 9 of 11 main draw matches on clay, defeated 4 top 30 players, and faced Rafael Nadal in his first ATP 500 final. Needless to say, tennis fans and commentators are taking notice. And amidst all of the speculation about how high Tsitsipas could rise, the youngster has already draw comparisons to several greats, including French Open champion Gustavo Kuerten.

Such comparisons could foretell more than a bright future for Tsitsipas. They could also suggest the type of opponent who could become an arch-rival of the youngster in his continuing career.

An arch-rival is more than a tough opponent. It is an opponent whose game a player just can’t seem to crack. The kind of opponent who seems to play with kryptonite up their sleeves.

In tennis, arch-rivalries are sometimes called “bad match ups”. In other words, a clash of styles that can cause the better overall player to actually be at a disadvantage. Think of the single-handed backhand of Roger Federer against the heavy spin of Rafael Nadal; or the unorthodox hitting of Kuerten against the powerful shots of Andre Agassi.

The game has seen many rivalries but only some have had the kind of clash of styles that we associate with arch-rivalries. But how can we tell the difference?

To find arch-rivals, we have to start by looking at how surprising each result has been in a head-to-head. A surprising result is one that goes the opposite direction of what a player’s overall strength, measured by official ranking or Elo rating, would suggest. The more puzzling the head-to-head results, the more it suggests that a clash of styles is involved.

Using historical Elo ratings to measure how unexpected match results were, the chart below shows the 10 most surprising head-to-heads in the Open Era of men’s tennis. All of the arch-rivalries include some of the biggest names in the sport. And two are match ups well recognised to be major clashes of style: Ivan Lendl vs Boris Becker and Roger Federer vs David Nalbandian.

Many of the 20 meetings between Lendl and Becker were when Lendl was at the peak of his game. Still, the booming German found a way to keep their head-to-head nearly even. The script was very much the same for Federer and Nalbandian, with Nalbandian being even more of an outside favourite over the 19 times the pair faced off. But 8 of those times the Argentine took the win.

The most surprising among the 10 is one of the less talked about rivalries in men’s tennis history: Yevgeny Kafelnikov vs. Dominik Hrbaty. Despite being the higher ranked player in all of their 13 meetings, Kafelnikov managed to win only 4 matches against Hrbaty. It was a similar story for Kafelnikov against Thomas Johansson, who won 9 upsets from his meetings with out of his meetings with the Russian.

Other former No. 1s in the list include Jimmy Connors and Pete Sampras. The appearance of each of them among the above list suggests that even the best in the game can get tripped up by a tricky opponent who gives them more trouble than their ranking along would have predicted.

We should note the interesting fact that two of the surprising head-to-heads include Yevgeny Kafelnikov. Recently, Kafelnikov’s career has come into the spotlight after suspicions about his role in match-fixing were revealed in the Independent Review’s Interim Report. While that report raises the possibility that some players might intentionally underperform against lesser opponents, it also shows that this would be extremely unlikely among the top players in the sport.

Stephanie Kovalchik avatar
About Stephanie Kovalchik
Blog Founder, Senior Data Scientist at the Game Insight Group at Tennis Australia, and researcher at the Institute for Health and Sport at Victoria University.
Graeme Spence avatar
About Graeme Spence
Data Scientist in the Game Insight Group at Tennis Australia and researcher at the Institute for Health and Sport at Victoria University.
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