Novak Djokovic found his form, and some good fortune, against ailing Jo-Wilfried Tsonga

NEW YORK—Two weeks before the U.S. Open, at the Western & Southern Open in Cincinnati, heralded doubles star Martina Hingis and her partner CoCo Vandeweghe received a bye and two walkovers before playing their first match of the tournament in the semifinals. Novak Djokovic’s path to the final four in Flushing Meadows hasn’t been that easy—he has had to log six hours and 26 minutes of actual tennis over five rounds. But even in that length of time, nearly the duration of one five-set marathon, we’re getting a clearer picture of Djokovic’s actual form.

Despite receiving a walkover win in the second round and benefiting from two retirements—the latest on Tuesday night against No. 9 seed Jo-Wilfried Tsonga—we’ve seen Djokovic in a number of difficult tennis situations. And when he’s actually been forced to play, he’s done well in each tricky scenario.

In the first round, where nearly half of Djokovic’s nine completed sets have taken place, the top seed was far from his best against Jerzy Janowicz, who years ago might have made the Serb pay for his lethargy. But although Djokovic made a poor first impression, he nonetheless gutted out a four-set win, and in the process shook off some of the cobwebs of inactivity since the Rio Olympics.

In the fourth round, Djokovic seemed to be cruising to victory against Kyle Edmund before a stumble with the finish line in sight. But instead of letting the match linger like he did in the first round, Djokovic answered Edmund’s late break of serve with a pivotal one of his own, and continued in his path through the bracket with a three-set win.

Tonight, we thought, would be Djokovic’s first true test. His opponent, Tsonga, is an experienced and excellent hitter who was at his all-court best against Jack Sock in his previous match. The Frenchman unfortunately succumbed to a right knee injury after dropping the first two sets, 6-3, 6-2, but when he was at full capability, he got Djokovic’s attention. And after a sizable stretch of un-Djokovic-like tennis, we saw calm yet commanding game the 12-time Grand Slam champion has used to ascend into the stratosphere of the sport.

Serving at 3-4 in the first set, Tsonga saved two break points and had Djokovic on the run well behind the baseline. But not on the defensive, because of Djokovic’s uncanny ability to turn a point seemingly destined for failure into one destined for the highlights. When Djokovic rifled a backhand at Tsonga from an off-balance position, the complexion of the point changed instantly, with Tsonga tightening and Djokovic emboldened. Djokovic rode the eventual break to win the set, one in which Tsonga struck 19 unforced errors.

Another bit of Djokovic magic was witnessed at 4-2 in the second set, with Tsonga serving down 0-30. Again, Tsonga took control of the rally, but when Djokovic transitioned from scampering to attacking, the Frenchman was entrenched inside a losing battle. Djokovic’s kill shot was a beautiful lob, struck at a height Tsonga could not reach yet landing with sufficient margin. It enthused the crowd the deflated Tsonga, who let points and games go with shockingly little effort.

We soon realized that Tsonga’s right knee played a part in his lack of form. But we should also realize that these notable points—and plenty of other clinical yet drama-free points won by Djokovic—signal that he’s worked his way into form despite an almost laughable path to the semifinals. The Serb’s serve was clicking aganst Tsonga, he cut down on his errors and exuded the confidence of a top seed. You have to be lucky to be good—and, in Djokovic’s case, good to be lucky.