NEW YORK — For the third time in the past three seasons, Stan Wawrinka has done the toughest thing in tennis: stop Novak Djokovic in a Grand Slam tournament.

The latest victory came in the U.S. Open final Sunday, and Wawrinka’s 6-7 (1-7), 6-4, 7-5, 6-3 triumph gave him a third major singles title, at age 31.

He has had to solve the riddle of the elastic Djokovic to win them all. Wawrinka surprised Djokovic in the quarterfinals en route to the 2014 Australian Open title, stunned him in the final to win the 2015 French Open and has now beaten him in Arthur Ashe Stadium, too.

“Honestly, this is amazing,” Wawrinka said. “I came here without expecting, without setting a goal to win it, but every time I stepped on the court, I was trying to win every match. I think I played quite a lot of tennis these two weeks. I’m completely empty; I had to bring everything I had today against Novak.”

At this stage, it is hard to call this one an upset, and Djokovic stated the obvious before this final when he called Wawrinka “a big-match player.”

That was not always the case, but since joining forces with Swedish coach Magnus Norman in 2013, Wawrinka has found a way to rise to big occasion after big occasion. He is not a consistent threat, but when he is in the right form and rhythm, he is a major danger.

The most telling statistic: He is now 11-0 in his past 11 finals, and Sunday he managed to hold firm despite two late injury timeouts in the fourth set from Djokovic, who had treatment on both feet.

Wawrinka, seeded No. 3 here, might not have the resume of his fellow Swiss Roger Federer or Spain’s Rafael Nadal, but he has the ability to do consistent damage to Djokovic, the game’s supreme defender, from anywhere on the court. His forehand is heavy, and his one-handed backhand is one of the game’s great (and most telegenic) weapons. He can serve with enough force and guile to keep Djokovic from teeing off on too many returns and has deft enough touch at the net to push forward as well.

But Djokovic, the world’s No. 1 player, has so many strengths — and no real weaknesses — of his own, and he came out very strong Sunday, jumping out to a quick 4-1 lead and holding on to win the first-set tiebreaker to send Wawrinka an early message about the challenge ahead. It might have been an intimidating message to other leading players, but Wawrinka had lost the first set and rallied to win at the 2014 Australian Open and the 2015 French Open. He went on to do it again here.

Djokovic had every reason to feel fresh. Two of his opponents at this U.S. Open — Mikhail Youzhny and Jo-Wilfried Tsonga — retired mid-match. Another who had beaten him earlier in the season — Jiri Vesely — pulled out before their match began. He arrived at the final having spent very nearly half as much time on court as Wawrinka, who had to save a match point to escape from his third-round encounter against British outsider Dan Evans.

Djokovic certainly had physical concerns both before and during the event, including a left wrist problem that had him and his team seriously debating whether he should withdraw before the Open began.

Instead, he decided to play and got lucky, getting plenty of extra time to recover during the tournament. But his luck ran out against Wawrinka, who is now missing only one Grand Slam title — Wimbledon — from his expanding collection.