Jo-Wilfried Tsonga was struggling against Kei Nishikori—the highest-ranked Japanese tennis player in ATP history.
Down 6-2, 2-6, 1-6, Tsonga absolutely needed to refocus immediately to remain in this tournament. He had the physicality, will and endurance to come back and win this match in five sets.
But Nishikori is an impressive player who has fought back to win both his second and third-round matches, so there's no doubting he can go the distance as well. This lapse in focus on Tsonga's part dashed his hopes of a first Grand Slam into question.
He was one of the favorites to perhaps win this tournament, after the top four players in the world. The court is conducive to his playing style, allowing him to hit heavy walloping forehands. Tsonga is also no stranger to high-stakes match situations, having come back two sets down against Roger Federer in the quarterfinals of Wimbledon last year.
There was a chance that Nishikori could get tight in the last two sets, succumbing to both the sheer importance of the moment and his fatigue from previous tough matches.
Tsonga needed to cut down on his unforced errors, which were at 42 after 3 sets, as compared to Nishikori's conservative 19. He was taking a few too many risks on service games and getting easily exploited and broken. In addition, Tsonga should have been aggressive as he approached the net, bending down low to get drop shots and finishing points off with his powerful stroke.
This proved to be a great fourth-round match, stretching five sets as Tsonga attempted to refocus and reclaim control of the competition.
Nishikori continued to push Tsonga physically, and his lack of experience did not get the better of him.
UPDATE: Nishikori takes down Tsonga in the fifth set, 6-3 to move onto his first Grand Slam quarterfinal. He will face Andy Murray in his next match.