Ben Shelton beats defending champ Carlos Alcaraz in U.S. Open match that ends after 3:30 a.m.

Ben Shelton had gone toe-to-toe with Carlos Alcaraz for five exhausting sets and finally, at 3:33 a.m. ET Wednesday, came the chance to end the U.S. Open champion's title reign.

Shelton fired an ace at 146 m.p.h. — a ball that Alcaraz couldn't have gotten back even with fresh legs.

That gave Shelton a 6-7 (5), 6-1, 6-3, 1-6, 7-6 (10-7) victory in a marathon tussle that was the latest-finishing match in U.S. Open history.

"I'm tired. It was a war," Shelton said. "Carlos is one of the greatest champions of our sport. It was the most enjoyable match I've had in my career, for sure."

Alcaraz had his 18-match winning streak in Grand Slam tournaments end in a match that lasted 4 hours, 28 minutes. He fought deep into the night and early into the next morning in a bid to get his hands on the trophy again, battling back even as he vomited before the start of the final set.

Alcaraz started the year winning the Australian Open, but was playing his first tournament since April after returning from a right wrist injury.

"I'm leaving happy and my head held high," Alcaraz said. "The truth is, I wanted to win … but also our goal was to leave the tournament having played matches and staying healthy."

The U.S. Open craves its night matches and players love the energy the fans provide — even when a number of matches have already gone past 2 a.m. this year.

Thousands stayed to the end, with Arthur Ashe Stadium perhaps still one-third full for the finish. Shelton benefited from a home-crowd boost even against the popular Alcaraz, with fans chanting his name along with "USA! USA!"

"It's incredible," Shelton said. "I always say that this is the greatest sports city in the world; I say that this is the greatest stadium in the world. I'm just