Defending champion Elina Svitolina made it through the group stage at the WTA Finals without dropping a set, beating replacement Sofia Kenin 7-5, 7-6 (10) on Friday to take her record to 3-0.
Svitolina, who had already qualified for the semifinals from the Purple Group, saved two set points in the second set before finally winning the match on her sixth match point.
Svitolina will next face Belinda Bencic on Saturday.
Later Friday, Simona Halep will play Karolina Pliskova for the final spot in the semifinals. The winner will meet top-ranked Ash Barty.
Kenin was playing her only match of the tournament after replacing the injured Bianca Andreescu.
The 12th-ranked Kenin, who earned $165,000 for her appearance, was the second alternate to see action this week. Kiki Bertens took Naomi Osaka's place after the Japanese player withdrew with a right shoulder injury ahead of her second match. Bertens ended up retiring with a virus against Bencic during her second match on Thursday.
