RIYADH, Saudi Arabia (AFP) — Aryna Sabalenka and Jessica Pegula both advanced to the Last Four of the WTA Finals with straight-sets victories in Riyadh on Thursday.

The top-seeded Sabalenka ended the title defense of Coco Gauff by defeating the American 7-6 (7/5), 6-2 in the closing match of the round-robin stage at King Saud University Indoor Arena.

With a perfect 3-0 record, Belarus’ Sabalenka finished atop the Stefanie Graf Group, while Pegula secured the runner-up spot with a 6-2, 6-3 victory over Italian eighth seed Jasmine Paolini.

Sabalenka set up a US Open final rematch with fourth-seeded American Amanda Anisimova, while Pegula will take on sixth-seeded Elena Rybakina of Kazakhstan in Friday’s semifinals.

“She’s always making me work hard, always great battles against her, I enjoy fighting against her. I’m super excited to face her in the semis,” said Sabalenka, who lost to Anisimova in the Wimbledon semifinals before beating her in the US Open title decider.

In what was the 12th career meeting between them, Sabalenka twice erased a one-break deficit against Gauff to force a tiebreak, and the Belarusian wrapped up the opening set in 55 minutes.

The four-time major champion leapt to a 4-0 lead in the second set and despite a brief fightback from Gauff, who narrowed the gap to one break, was able to reestablish control over the match to move into the Final Four.

“I was just trying to stay aggressive, to find my rhythm, find my game. I was kind of working for the second set already but I was able to turn it around,” said Sabalenka of her opening set struggles against Gauff. 

“I’m happy to make it through the round robin stage.”

Earlier in the day, Pegula defeated Paolini and, in the process, avenged her recent defeat to the world No. 8 in the Billie Jean King Cup Finals in Shenzhen.

“I’m really happy and excited to be through into the semis here. I knew I needed to win today, especially in straight sets, so that was kind of my main motivation and I’m glad I was able to play some really good tennis,” said the 31-year-old American.

The former US Open finalist is competing in the WTA Finals for a fourth consecutive season and believes the caliber of the field this year has been stronger than previous ones.

“I felt like this year was so competitive. I felt like this group has been so strong all year and we’ve all had a time of the year where we’ve played such a high level,” said Pegula, who has won three titles on three different surfaces this season.

“I do feel like the level has been crazy, crazy deep this year. It feels a little bit harder than maybe past years.”

With Gauff and Poland’s Iga Swiatek both out of the competition, a first-time WTA Finals champion will be crowned on Saturday in Riyadh.