WTA Finals: Iga Swiatek and Coco Gauff secure semi-final spots in Cancun

Poland's Swiatek confirmed her position with a 6-1 6-2 win over world number six Ons Jabeur.

Earlier, Gauff claimed a victory in a battle of two of the major champions from this year.

She defeated Marketa Vondrousova 5-7 7-6 (4) 6-3 in the final round of group play on Friday night, ending the Czech player's chances of advancing to the last four.

The win was another feather in the cap for Gauff, making her the first teenager to make the final four of the year-end championships since Caroline Wozniacki in 2009.

"I felt like I needed to hit through the court," Gauff said. "She's a very tricky player. When you play her pace and let her move you side to side it's tough. And I played her, it's my third time, so I know that.

The 19-year-old Gauff will now face Jessica Pegula while Swiatek takes on Aryna Sabalenka.

"We'll see what the conditions are going to be," Swiatek said. "Against Aryna it's never easy. I'm just gonna 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."