Iga Swiatek will finish the year at No. 1 after beating Jessica Pegula to win the WTA Finals

CANCUN, Mexico (AP) — Right after relinquishing the No. 1 ranking two months ago, Iga Swiatek couldn't help but worry about trying to regain it.

"It's hard not to think about stuff like that," she explained.

And then Swiatek realized it was better to set that sort of thing aside and, instead, simply focus on playing her best tennis—and her best is better than anyone else's at the moment. Swiatek earned her first WTA Finals title and clinched the year-end No. 1 ranking by overwhelming Jessica Pegula 6-1, 6-0 on Monday in the latest in a series of dominant performances.

"Today was like a highlight of this mental (approach)—just being narrow with your head, only thinking about the right stuff," said Swiatek, a 22-year-old from Poland who is the youngest WTA Finals champion since Petra Kvitova was 21 in 2011.

Swiatek went 5-0 at the tour's season-closing championship, winning all 10 sets she played and ceding a total of just 20 games. That's the fewest by the winner at the event for the top eight women in tennis since the round-robin format returned in 2003.

"She clearly really wanted that ranking," Pegula said. "I mean, you could tell by the way she was competing here. ... She was, like today, crushing people."

Swiatek extended her winning streak to 11 matches and improved to 68-11 in 2023 with six trophies, including her fourth career Grand Slam title at the French Open in June.

Pegula called it "an amazing year."

This victory allows Swiatek to return to No. 1, a spot she held from April 2022 until this September, when Aryna Sabalenka overtook her after the U.S. Open. In Cancun, Swiatek defeated Sabalenka in a semifinal that began Saturday, was suspended by rain, then finished on Sunday.

Pegula, a 29-year-old American, hadn't dropped a set entering Monday.

By beating No. 1 Sabalenka and No. 4 Elena Rybakina in the group stage, eliminating her doubles partner, No. 3 Coco Gauff, in the semifinals and taking on No. 2 Swiatek, Pegula became the first woman to face each of the top four players in the world at one event since the start of the WTA rankings in 1975.

But Pegula's nine-match winning streak was stopped emphatically by Swiatek.

Swiatek finished with more winners, 9-6, and far fewer unforced errors, 23-6. She broke Pegula five times while only facing one break point herself — and it came as Swiatek served for the match in the last game.

Swiatek won 25 of 36 points in the first set, and 26 of 36 in the second.

"It just was one of those days where I felt like I was going for too much," Pegula said. "And she was just playing super solid."

When it ended, Swiatek dropped to her back, then sat up and yelled. Some spectators waved red-and-white Polish flags. During the trophy presentation, fans showered her with chants of "Iga!"

The final was played under a mostly blue sky and with far less wind than players were forced to contend with throughout the week. And, most importantly, there wasn't a drop of rain.

Laura Siegemund of Germany and Vera Zvonareva of Russia won the doubles title by beating Nicole Melichar-Martinez of the U.S. and Ellen Perez of Australia 6-4, 6-4.

The singles and doubles title matches both originally were scheduled to be contested Sunday, then were pushed back after a series of showers affected play.

"It hasn't hasn't been the easiest week," Pegula told the crowd, "for any of us."