Iga Swiatek entered the U.S. Open as its current champion, as the victor of three of the previous six Grand Slam competitions, and as the No. 1 ranking holder for about one and a half years.

All of that was irrelevant against Jelena Ostapenko on Sunday night because of the way that Ostapenko disturbs Swiatek’s rhythm and consistently outperforms Swiatek.

Swiatek lost to 2017 French Open winner Ostapenko in the fourth round at Arthur Ashe Stadium, putting a stop to his title defence at Flushing Meadows. As a result, Swiatek’s reign as WTA No. 1 will come to an end the following week, when Aryna Sabalenka, who is currently No. 2, will take the top spot for the first time.

“The main thing is that she doesn’t really like to play against big hitters. … She likes to have some time,” said the 20th-seeded Ostapenko, a 26-year-old from Latvia. “When I play fast, aggressive and powerful, she’s a little bit in trouble.”

Swiatek only received 18 victories, compared to Ostapenko’s 31.

More significantly, Ostapenko finished with just 20 unforced errors, which is a significant improvement from the 80 she made in last week’s second-round victory.

Ostapenko grinned and remarked, “Not bad,” in response to a reporter mentioning the Sunday total. Given their prior encounters, this was perhaps not entirely unexpected: Ostapenko now has a career record of 4-0 versus Swiatek.

No other athlete had four wins over the female leader of the WTA rankings since April 2022.

Ostapenko faltered briefly in the second set after a strong start that saw her lead it 4-1. As a result, Swiatek was able to recover the break and move ahead 4-3.

But that was just a little hiccup.

The match immediately leaned in one direction as Swiatek struggled to serve, maybe as a result of all the squeaking Ostapenko’s shoes made while she moved around during the ball throw while waiting to return. Ostapenko won seven straight points to take a 5-0 lead in the third set.

Ostapenko broke for the last time to win the match, taking seven of Swiatek’s 13 service games.

At Flushing Meadows, Ostapenko will face American teenager Coco Gauff in the first round. Gauff defeated Caroline Wozniacki earlier in the day by scores of 6-3, 3-6, and 6-1.

Gauff and Ostapenko have split their prior two encounters. Ostapenko triumphed in the most recent match, which took place in the fourth round of the Australian Open in January.

“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.”