The loss also means Swiatek’s stay at No. 1 in the WTA rankings will end next week, when current No. 2 Aryna Sabalenka will rise to the top spot for the first time.

Swiatek’s shots were off-target in Arthur Ashe Stadium and she had a difficult time handling the hard hitting from the 20th-seeded Ostapenko, who won the 2017 French Open.

“I knew I have to play my game,” Ostapenko said after accumulating 31 winners to 18 for Swiatek. “I knew I have to be aggressive, because that’s what she doesn’t really like.”

This was not necessarily a huge surprise, based on their previous matchups: Ostapenko has now improved to 4-0 against Swiatek over their careers. No other player owns four victories against the woman who has led the WTA rankings since April 2022.

“I was just thinking that I have to play until the very last point, until we shake hands,” Ostapenko said. “I didn’t really give her many chances.”

After getting off to a terrific start to the second set, which she led 4-1, Ostapenko wavered for a bit. That allowed Swiatek to get a break back and pull within 4-3.

But that was only a blip.

With Swiatek having trouble serving — perhaps owing to all of the squeaking Ostapenko’s shoes did as she moved around during the ball toss while waiting to return — the contest quickly tilted in one direction. Ostapenko reeled off seven consecutive games to go up 5-0 in the third set.

Ostapenko broke one last time to end it, meaning she won seven of Swiatek’s 13 service games in the match.

Ostapenko’s first quarterfinal at Flushing Meadows will come against Coco Gauff, the 19-year-old American who eliminated Caroline Wozniacki 6-3, 3-6, 6-1 earlier Sunday.

Ostapenko and Gauff have split two previous meetings. The most recent came in the fourth round of the Australian Open in January, and Ostapenko won that one.

“She’s a great young player,” Ostapenko said about Gauff. “Of course it’s going to be another tough match. I don’t expect any easy matches at a Grand Slam.”