NEW YORK -- Ben Shelton ended Carlos Alcaraz's title reign in the latest-finishing match in US Open history, pulling out a 6-7 (5), 6-1, 6-3, 1-6, 7-6 (10-7) victory in a marathon tussle that ended at 3:33 a.m. ET Wednesday.
Alcaraz had his 18-match winning streak in Grand Slam tournaments ended in a match that started just after 11 p.m. and lasted 4 hours, 28 minutes.
Thousands of fans stayed to the end and Shelton benefited from a home-crowd boost even against the popular Alcaraz, with fans in Arthur Ashe Stadium 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 hoping that my best friend and my sister over there don't have to be at work at 6 a.m. in three hours."
Shelton next plays No. 11 seed Frances Tiafoe, who kept coming back until he had reached his third US Open semifinal, beating Alex Michelsen 5-7, 3-6, 7-5, 6-3, 7-6 (10-6) on Tuesday.
The U.S. is guaranteed to have a representative in Sunday's final as it seeks its first men's major title since Andy Roddick lifted the title here in 2003. The match between Shelton and Tiafoe on Friday will be the first major meeting in the semifinals or later between Black American men in the Open era. One will become the first Black American man to reach a US Open final since Arthur Ashe in 1972.
Alcaraz had played in the previous latest finish at the US Open when he outlasted Jannik Sinner in a match that finished at 2:50 a.m. in the 2022 quarterfinals en route to his first Grand Slam title at 19.
The latest finish in Grand Slam history happened at the 2008 Australian Open, when Lleyton Hewitt defeated Marcos Baghdatis in a match that ended at 4:34 a.m. local time.
Three of the four singles quarterfinals Tuesday went to match tiebreakers on a marathon day, which started with Aryna Sabalenka edging Wimbledon champion Linda Noskova to keep her hopes alive of a third straight U.S. Open title.
Alcaraz will have to wait for his next one.
Instead it was Shelton reaching his third major semifinal, having gotten to the final four in the 2023 US Open and 2025 Australian Open. He became the first American to beat the defending US Open champion in five sets since 18-year-old Peter Sampras defeated Mats Wilander in 1989.
Shelton seized control by winning nine straight games from early in the second set until he had a 3-0 lead in the third. But Alcaraz, in his first tournament since April after returning from a right wrist injury, battled back even as he vomited before the start of the final set.
Alcaraz ran off four straight points in the tiebreaker to go ahead 5-3, but Shelton came back behind some of his powerful serves that can exceed 140 mph, along with some mistakes from Alcaraz. Shelton eventually finished it off with a 146 mph serve his opponent couldn't get back.
Alcaraz is now 15-2 in five-set matches. He won his seventh Grand Slam title at the Australian Open to start this year not long before his injury.
No man has defended his US Open title since Roger Federer won five straight from 2004-08. The run of 18 straight US Opens without a repeat champion is the second-longest streak in tournament history, after 19 straight from 1961-79, before John McEnroe defended his title in 1980.
McEnroe, who played at Stanford, is also the last former college player to win a major singles title (1984 US Open). Shelton, a former national champion and player of the year at Florida, will be looking to follow him, as the lone former college player left in either the men's or women's singles draw.
ESPN Research and The Associated Press contributed to this report.
