Kei Nishikori’s Unbeatable Run in Deciding Sets

Italian translation at settesei.it

When Kei Nishikori defeated Roberto Bautista Agut in last week’s Barcelona quarterfinals, it was the seventh time in a row that he won a deciding set. By Nishikori’s standards, that’s nothing special. It is the fifth time in his career he’s put together a string of at least seven straight deciding-set wins, three of which he’s recorded since the beginning of last season.

The wider the perspective, the more impressive Kei’s deciding-set record. Since last year’s Australian Open, he’s won 27 of 30 matches that went the distance, including a 13-match winning streak from Halle to London. Back in 2011-12, he won 16 deciding sets in a row, including four against top-ten players.

In his career on tour, Nishikori has won 75 deciding-set matches and lost 20, for a winning percentage of 79%. Using any reasonable minimum number of matches, no other player has come close to that mark. You might recognize some of the other names on this list, ranked by record in deciding sets (minimum 80 matches):

Kei Nishikori   78.9%  
Bjorn Borg      74.7%  
Novak Djokovic  74.1%  
Jimmy Connors   69.8%  
Rafael Nadal    69.5%  
Andy Murray     69.4%  
Rod Laver       68.4%  
John McEnroe    68.1%  
Pete Sampras    68.0%

Kei’s career accomplishments don’t quite stack up with those of this crowd, but in terms of deciding-set performance, we’re looking at much more than an early-career fluke. While his numbers are a bit padded by matches that shouldn’t have gone the distance (like his early-round hiccups in Memphis this year against Ryan Harrison and Austin Krajicek), he has been almost as good when facing the best players in the game. Against top-ten opponents, he’s 17-6, good for a 74% winning percentage–a mark that would still put him near the top of the list.

Let’s return to Nishikori’s outrageous recent record of 27-3 in his last 30 deciding sets. Sure enough, no one has ever done better. Nine other players  have posted an equal mark in a span of 30 deciding-set matches, including Novak Djokovic, Rafael Nadal, Roger Federer, and Nishikori’s coach Michael Chang. Amazingly, Kei himself had already gone 27-3, back in 2011-12.

To break the tie among these accomplishments, we might look at the difficulty of the 30-match span, as measured by deciding sets against top-tenners. When Djokovic went 27-3, between 2011 Dubai and 2012 Canada, he played 15 of those matches against top-ten opponents,winning 14 of them. (Novak is also 27 of his last 30, including 15 of 17 against top-tenners.) When Nadal had his run, between 2008 Dubai and 2009 Paris, he faced 12 top-tenners, beating 10. Kei has faced only six, winning five.

It’s clear that Nishikori’s deciding-set prowess is a skill, not just a statistical fluke built on easy draws and luck. And based on the performance of the other players who have put together equally impressive deciding-set streaks, we can expect Kei to win most of his upcoming three- and five-setters.

Including streaks that overlap, there have been 27 instances in ATP history when a player won 27 of 30 deciding-set matches, excluding Kei’s and Novak’s current spans. In the ten deciding-set matches that followed each of those streaks, in each instance the player won at least five, and the average was just under seven.

Only once in ATP history has a player gone 27-3 in deciding-set matches and followed it up by winning nine of his next ten. If Nishikori is to match or better that mark, at least he’s assembled the right team: The player he’s chasing is Michael Chang.