Legend
Join Date: Dec 2006
Posts: 5,405

A good piece on the TsongaFederer match, from The Daily Fix blog at WSJ:
Djokovic’s Many Happy Returns.
By Carl Bialik
JoWilfried Tsonga’s serve looked unbreakable for most of his Wimbledon quarterfinal upset of Roger Federer on Wednesday. Two days later, Tsonga was broken six times by Novak Djokovic, who claimed the No. 1 ranking and his first Wimbledon final berth with the win. The difference is mostly due to Djokovic’s superior return game, the best in tennis. But it also reflects the importance of winning points at the right time, something Federer didn’t do against Tsonga but Djokovic did.
In two days, JoWilfried Tsonga’s serve devolved from extraordinary to ordinary.Federer won 29% of points in Tsonga’s service games, compared to 39% for Djokovic. That may sound like a moderate difference, but it turns out to be enormous. Breaking serve requires winning four return points, or more, in the same game and outscoring the server by at least two points. So any small edge in returning on any point accumulates over the course of a game. If Federer had the same 29% chance of winning any particular point in Tsonga’s service games, then he had a 9% chance of breaking in each of those games. Djokovic’s chance, assuming his probability of winning any Tsonga service point was 39%, was 25% — nearly three times as great as Federer’s. That means Federer could have expected to break Tsonga twice, and Djokovic five times (Tsonga had more service games in his fivesetter against Federer than in his four sets against Djokovic). The actual numbers were close: One and six, respectively.
But on grass, where big servers often thrive and one break can be enough to win a set, Federer’s inability to get that second break may have prevented him from winning the match, while Djokovic’s extra break helped him close out Tsonga in four. The discrepancies reflect that Djokovic clustered his return points well: Tsonga had some easy service games against him, but Djokovic dominated him in others. Federer, instead, consistently scored one or two points on most Tsonga service games but never even had another break point after breaking Tsonga in Tsonga’s first service game. Given the number of return points he won, if Federer had clustered them randomly he could have expected to hold at least one break point in six different Tsonga service games. His probability of holding a break point in just one (or none) was 1%, yet that’s what happened. Tsonga, against Federer, clustered his return points well — he won just 24% of his and could have expected just one service break. Instead he broke three times and beat Federer, despite losing 10 more points than he won.
Sadly for Federer, this has become the norm at the tournament he once owned. This is the fourth straight Wimbledon in which he broke just once in his final match at the tournament. In 2009, that break was enough to beat Andy Roddick in five sets. But in the 2008 final against Rafael Nadal and in Federer’s 2010 quarterfinal against Thomas Berdych, one break didn’t suffice. And each time, Federer had fewer breaks than would be expected from the proportion of return points he won. Against Berdych he should have had three; against Roddick, three; and against Nadal, four. This is a result of Federer’s recent record of poor rates of breakpoint conversions in big matches at majors, but also of too many games in which he never quite got to break point. If Federer wants to beat the likes of Tsonga next year, as well as Djokovic and Nadal, he’ll have to find a way to pack his return points into single games, and make the most of them.
At Wimbledon last year Federer finally broke this pattern. He broke Djokovic 3 times, Murray 4 times.
