There are a number of strategic reasons why Rafael Nadal has now lost seven straight matches to Novak Djokovic. But for the purposes of this article, let's incorporate a bit of expert analysis to focus on one particular aspect of Nadal's game that has hurt him against Djokovic.
His service game.
We start with Jon Wertheim of Sports Illustrated, who notes that Nadal's serve has significantly decreased in velocity:
The last time Nadal beat Djokovic in a major, the 2010 U.S. Open final, Nadal served hellaciously and took advantage of what was then a superior heart. Djokovic is a different player now, a more courageous player. But why Nadal is serving drastically slower than he did 18 months ago (shoulder injury? a tactical decision? lack of belief?) is mystifying.
This lack of velocity in his serve played right into one of the strengths of Djokovic's game, his ability to crush an opponent's second serve. From Patrick Mouratoglou of Yahoo!:
Nadal's serve, especially his second serve, lacks depth and power; Djokovic, meanwhile, boasts the best returning stats on second serve. Throughout 2011, Nole won the most points on his opponents' second serve. Against Rafa, he's "having fun" when he takes these chances, and always starts these points as the offensive player. The Spaniard, when challenged like this, plays short and gets punished.
It held true for Nadal again. The two players had an almost identical first-serve winning percentage, with Djokovic coming in at 68 percent and Nadal finishing at 66 percent.
But there was a dramatic difference in second-serve winning percentage. Djokovic remained consistent at 63 percent, but Nadal dropped drastically to 45 percent.
Nadal seems to be in a pickle—if he tries to improve his velocity on his first serve, he risks having to rely on a second serve that Djokovic routinely feasts on. If he continues to try to keep his first serve consistent, he may do so at the risk of lacking the power on the serve needed to keep Djokovic off balance.
Nadal was as close to beating Djokovic as he's been in some time. But if his serve doesn't improve against Djokovic, it may be as close as he gets.
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