WIMBLEDON, England—Novak Djokovic and Andy Murray are the same age, are two of the best returners in tennis, and haven’t dropped a set so far this Fourtnight. And for a while the similarities extended to their fourth-round matches. Murray, as I wrote earlier, had one difficult set sandwiched around two easier ones. That’s precisely how I would have described Djokovic’s tussle with Tommy Haas, before the 35-year-old’s final push, one that nearly took a fairly straightforward content into the unknown.

Djokovic could not have started this dangerous round-of-16 match better. The world No. 1 owned a 5-3 record against Haas, but lost both of their matches on grass, at Halle and Wimbledon four years ago. The Serb is unquestionably a better player since then, but that statistic gave cause for concern, especially considering Haas’ recent win over Djokovic in Miami.

Playing like he couldn’t afford to lose a point, Djokovic was in full flight throughout the first set, his groundstrokes singeing the lawn and his returns shattering Haas’ serve. The top seed broke serve three times in the set and won 29 points to Haas’ 16; in 25 minutes, it was 6-1.

Speaking after the match, Djokovic knew Haas’ game would pick up once the second set began, and he was right. The German broke serve for the first time at 2-2 and consolidated for 4-2, with Djokovic starting to press on his previously pristine shots from the baseline. But with Haas serving at 4-3, Djokovic had a look at 0-40. After two uncharacteristic returns into the net, Djokovic and Haas engaged in what may have been the best rally of Manic Monday, a sequence of at least 30 shots that sent both men from side to side in order to intercept heavy shots over, and over, and over again. You could hear the effort, not with grunts but with sublime contact, the sounds of sweet spots wafting through the rows of astonished onlookers. It was wrong for a rally of this caliber to end on an unforced error, but Djokovic made up for it two points later when he converted a break chance by winning a shorter but just as punishing exchange.

When Djokovic broke Haas for the second set at 5-4, and took a 5-3, 30-0 lead in the third, the comparison to Murray’s match was unmistakable. And then it was a thought to be forgotten. Haas won seven of the next eight points, many off tight Djokovic errors, to break just in time and bring a supportive crowd to roaring levels. When Haas saved a match point with an unreturned serve and then held for 5-5, the fans had visions of a roof dancing in their heads. The time it would have taken to close it would have given Djokovic a lot of unnecessary time to think about a significant opportunity he’d let go.

Maybe Djokovic thought about that on the changeover at 6-5, for while he wasn't able to prevent a tiebreaker, he played some of his best tennis of the match in the late stage. Starting with an ace and building his lead with impregnable defense, Djokovic demanded Haas prove his worth one more time, and it was a time too many. That defense (which often turned seamlessly to offense) got into Haas’ head at 4-1, when the veteran overhit a forehand into the open court. If he was looking at Djokovic—heading to where the ball would land before Haas knew it himself—instead of the ball, it was an understandable if fatal sin. Haas’ fate was sealed, 6-1, 6-4, 7-6 (4), when Djokovic hit a stone-cold backhand winner and let out a roar of success.

!IBM Stat of the Match:Djokovic got a little sloppy in the latter stages, but hit only 16 unforced errors in the match—and has now made just 19 in his last two.

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