Ben Shelton has triumphed in a five-set thriller that set a new US Open record as the latest finish ever to a match at the New York grand slam. 

The clock passed 3am local time midway through the final set, as Shelton advanced to the semifinals at Flushing Meadows with a 6-7 (5-7), 6-1, 6-3, 1-6, 7-6 (10/7) win. 

Alcaraz won the first set in a tiebreaker, before the big-serving American eighth seed roared back into the match.

Shelton had the New York crowd in his corner as he took a 2-1 lead in sets, as Alcaraz looked tired and sluggish. 

But the Spaniard, a two-time winner at Flushing Meadows (2022 and 2025) dominated the fourth set to set up the thrilling finish.

Neither player dropped their serve in the final set, but both had a break-point opportunity during the decider.

But a 10-point tiebreaker was needed to separate the two.

The tiebreaker was on serve at 3-3 when the players swapped ends, each having won a point off the other's serve.

Alcaraz had a chance to make it 7-5 with a mini-break, but his backhand went long as the players swapped ends again at 6-6.

Shelton then got a mini-break and made it stick, giving himself a chance to serve for the match at 9-7, which he converted with an ace.

The 4 hour and 28 minute battle finished at 3:34am in New York.

Alcaraz was also part of the previous latest finish at the US Open, when his quarterfinal win over Jannik Sinner in 2022 finished at 2:50am.

Shelton will face American Frances Tiafoe, who came from two sets down to win his own five-set quarterfinal.

Tears flow as tennis star lets two-set lead slip in first major quarterfinal

Frances Tiafoe has cut short his celebration to console friendly rival Alex Michelsen after coming back from two sets down to reach the US Open semifinals for the third time.

The 11th seed recovered time and time again to beat Michelsen 5-7, ​3-6, 7-5, 6-3, 7-6(10/6) and end the 22-year-old's first trip past the second round at his home slam.

Unseeded world number 46 Michelsen, whose previous best at a grand slam was a fourth-round berth at the 2025 Australian Open, was up a break in the third set and served for the match at 5-4 but Tiafoe won seven straight games to stay alive and take a commanding lead in the fourth frame.

Michelsen refused to go away though, taking a 3-0 in the decider, only for Tiafoe to once again storm back and take the set in a 10-point tiebreak.

After drilling a forehand passing shot down the line to secure the win after four hours and 38 minutes, Tiafoe began to celebrate his great escape before cutting his elation short to embrace his compatriot, who cried into his shoulder.

"As soon as I hugged him I saw he was crying already," Tiafoe told ESPN.

"I was like 'Man I know. I've been there twice, lost in five.' … He's young and he hasn't been there. 

"We're super tight. We've always had a great relationship. We laugh and joke all the time. He's one of my good buddies on tour.

"I know how much that hurts. I know how much he wanted that today. It's something that you dream about.

"I just told him, 'You're going to be here so many more times, man. And I'm going to be in a rocking chair when you do.'"

Tiafoe appeared to have lost all the magic of his early campaign before ​wresting the momentum in ‌the third set and clinching it with a forehand winner to the deafening cheers of the fans at Arthur Ashe Stadium.

Michelsen had flown under the radar in his deepest major run but ‌he earned respect on the biggest stage of American tennis with 21 aces and 55 winners against Tiafoe, although he counted the cost of 61 unforced errors in the marathon match.

"I slowly, slowly started ​getting my rhythm there," ‌said Tiafoe, who will next play either eighth seed Ben Shelton or defending champion Carlos Alcaraz.

"He's a hell of a player. I mean, he easily could have won today."

Michelsen said after his fourth-round victory that he had improved and would try to change things, but was glad to have shared the court with a friend.

"I was trying to keep it together and I didn't do a good job of that," Michelsen said.

"He's also an unbelievable guy and a very good friend of mine," he added.

Michelsen left the court with a towel on his head, raising his arm to acknowledge the cheers from the crowd.

ABC/Reuters/AP