Linda Noskova booked her place in the WTA Finals semifinals with a 6-3, 6-3 victory over Coco Gauff on Tuesday, while Jessica Pegula eliminated Marta Kostyuk from the season-ending tournament with a straight-sets win.
The Czech has made an impressive start to the competition, following up her opening victory over Kostyuk with another straight-sets triumph to secure two wins from two matches without dropping a set. She is assured of advancing to the knockout stage.
Gauff and Pegula both have one win and one loss, leaving the battle for the remaining semifinal spot to be decided in Thursday's final round-robin matches.
Earlier, Pegula revived her campaign with a 6-2, 7-5 victory over Kostyuk, bouncing back from her opening-match defeat to Gauff and ending the Ukrainian's hopes of reaching the semifinals.
The American made a strong start, breaking Kostyuk in the opening game before earning another break to take the first set. She carried that momentum into the second, breaking serve again at the start before the pair exchanged breaks twice.
Kostyuk's mistakes undermined her attempts to fight back, with the Ukrainian committing 17 unforced errors in the opening set compared with Pegula's three.
"Once I got off to a good start today, I definitely didn't want to give away that second set," Pegula said. "In general, I wouldn't want to, but I think it was a bit of an extra push to be able to give myself the best chance in this group, considering I did lose the first match."
Noskova then took control against Gauff in a match marked by inconsistent serving from both players. The pair traded breaks early in the first set, but Noskova broke twice more to take the opener.
Gauff again struggled to find consistency on serve in the second set, allowing Noskova to build a 3-0 lead. The American fought to stay in the contest but could not find a way back as Noskova held serve for the remainder of the set before sealing the victory with an ace.
The result sends Noskova, making her tournament debut, into the semifinals, while Gauff will have another chance to qualify when she faces Kostyuk on Thursday. Pegula takes on Noskova in the other final Group 1 match.
Kostyuk, who replaced Elena Rybakina after the world No. 1 withdrew with a viral illness, is making her first appearance at the WTA Finals.
"I saw that she's changing pace a lot, and I would struggle sometimes," Kostyuk said after her defeat to Pegula. "Overall, I think I was pretty happy with my return today. You can obviously be better, everything can be better. Next time, maybe I'll be more ready."
