US Open champion Coco Gauff beat Wimbledon winner Marketa Vondrousova to reach the semi-finals of the season-ending WTA Finals in Cancun, Mexico.

Poland's Iga Swiatek beat Ons Jabeur 6-1 6-2 to book her semi-final spot.

She will now play top-ranked Aryna Sabalenka, who defeated Elena Rybakina 6-2 3-6 6-3 to secure her progress.

Gauff's win against Vondrousova made her the first teenager to make the final four of the championships since Caroline Wozniacki in 2009.

"In the wind, it's tough to be as aggressive as you want, because the bounces are weird and the ball was moving," Gauff said.

"So I'm glad I made that adjustment and didn't get too frustrated when I missed. You pay the price for hopefully a good reward."

The defeats for Vondrousova and Tunisian world number seven Jabeur meant they were eliminated following the final round of matches in their group.

Swiatek could usurp Sabalenka at the top of the women's rankings if she beats the Belarusian and goes on to win the event.

"We'll see what the conditions are going to be," Swiatek said. "Against Aryna it's never easy. I'm just going to do my best and focus on myself and what I want to do on court.

"We usually have these matches that are really exciting and really tough, both mentally and physically."

Sabalenka led 6-2 3-5 against Rybakina when play was suspended at 23:40 local time on Thursday because of stormy weather.

The Kazakh levelled the tie within two minutes of play being resumed, but Sabalenka eventually claimed a 6-2 3-6 6-3 victory.

"I didn't really think a lot about this match," she told Tennis Channel.

"I was just like, whatever. I'm going to go out there and do everything I can and if I win, I win and if I lose, I go home on vacation.

"I was just trying to play as good as I can."

The Belarusian, who is set to retain her world number one ranking if she reaches the final, joined group winner Pegula in the semi-finals.

Rybakina and eighth-seeded Greek Maria Sakkari were eliminated from their group.