Coco Gauff posted a rare victory over Iga Swiatek to punch her ticket to the semifinals of the WTA Finals in Riyadh on Tuesday, ensuring Aryna Sabalenka will finish the year as the world No. 1.

Swiatek, the defending champion, was in a direct battle with Sabalenka for the top spot this week but needed a win over Gauff to keep her chances alive of leapfrogging her Belarusian rival.

Gauff, 20, entered the contest having lost 11 of her 12 previous meetings with Swiatek, with the American's sole victory coming in Cincinnati last year.