NEW YORK – When his opponent served, Frances Tiafoe was only one point away from losing the second set, but his record was positive.

At least, he thought, he could take off his sweaty shirt and sneakers.

A few minutes later, he hadn’t changed his clothes. He had changed around the game.

Tiafoe recovered, stole the second set and made it to the US Open quarterfinals for the third consecutive year by defeating Alexei Popyrin 6-4, 7-6 (3), 2-6, 6-3 on Sunday night.

“The second set was a huge, huge win for me,” Tiafoe said. “You know, 5-3, 40-0, his serve, how well he serves, that was really, really great. To get the break there and then win the set was huge.”

The 20th seed will attempt to match the best Grand Slam result of his career when he faces 9th seed Grigor Dimitrov for a place in the semifinals on Tuesday.

Tiafoe lost in this round to eventual champion Carlos Alcaraz in 2022 and was eliminated in the quarterfinals by Ben Shelton last year.

Tiafoe is the first American since Andy Roddick from 2006 to 2008 to reach the quarterfinals of the US Open three times in a row. Pete Sampras and Andre Agassi are the only other Americans since 2000 to reach the last eight in New York three times in a row.

And all this after a weak first half of the season, before Tiafoe really turned it on on the hard court in the run-up to the US Open.

“Everything happens when it’s supposed to happen,” Tiafoe said. “I’m glad it’s happening now because this is the most important time for me.”

Tiafoe didn’t need any extra motivation before Sunday’s match, but said a surprise visit and an unexpected speech from 23-time major winner Serena Williams inspired him like never before.

“She told me that she always follows me no matter what. She told me that now that I’m done, it’s so nice to see that I’m the colored guy who’s playing and doing well,” he said.

“I’m like, ‘Damn. That’s really, really cool that she sees me like that.'”

Williams returned to the tournament on Saturday for the first time since her last match at Arthur Ashe Stadium two years ago and was spotted again watching the action on Sunday.

“It was really cool that she wanted to talk to me before a match and really told me that she wanted me to do this and that I was capable of doing it,” Tiafoe said. “I don’t think it would affect me as much if someone else said that to me.”

However, Williams may be torn about who to cheer for when Tiafoe and Dimitrov meet in the next round, as she considers the Bulgarian a long-time friend. He said she also gave him a pep talk on Saturday and was in the stands when he beat Andrey Rublev on Sunday.

Tiafoe turned his game around late in the second set when Popyrin served with a 5-3 lead and had a chance to tie the set. Tiafoe won the next five break points and quickly took control of the tiebreak, building a 4-1 lead.

Popyrin, the 28th seeded Australian, defeated defending champion Novak Djokovic on Friday to reach the fourth round of a Grand Slam tournament for the first time, but he believes he might have gone further had he won the second set.

“Definitely a missed opportunity,” said Popyrin. “I’ve been saying all week that you have to take your chances when you have them against these top players. 5-3, 40-0 on serve, that’s a real letdown from my side.”

No. 12 seed Taylor Fritz won on Sunday, and another American, Tommy Paul, will face No. 1 seed Jannik Sinner of Italy in the fourth round on Monday. Should Paul win that round, he would join Tiafoe and Fritz in putting three men from the United States in the quarterfinals at Flushing Meadows for the second year in a row.

The last time so many players from the host country were represented in the quarterfinals of the men’s US Open was in 2001 and 2002.

Associated Press and Reuters contributed to this report.