The defending champion, Iga Swiatek, was eliminated from the WTA Finals after Barbora Krejcikova defeated Coco Gauff to clinch her place in the last four.

Swiatek had previously needed less than an hour to finish off Daria Kasatkina, who had replaced the injured Jessica Pegula 6-1, 6-0 in the opening match of the day in Riyadh.

But her chances of progress depended on the second match, and her luck ran out as Wimbledon champion Krejcikova battled to a 7-5, 6-4 victory over Gauff, whose place in the semi-finals had already been secured.

All three women finished the group stage with two wins from three matches, but Krejcikova, the tournament’s lowest ranked player, topped the group by virtue of best set percentage, while Swiatek was the one to miss out.

Krejcikova of the Czech Republic will face Olympic champion Zheng Qinwen in the last four on Friday, while Gauff meets world number 1 Aryna Sabalenka. Krejcikova’s shock win at Wimbledon was the notable highlight of what was largely a disappointing season for her.

But she has risen to the occasion in Saudi Arabia, bouncing back from a three-set defeat to Swiatek in her opening match to beat Pegula and Gauff to save 11 of 12 break points on Thursday.

“This is definitely a big win for me,” the 28-year-old said in her on-court interview. “I’m very happy with the way I played. Being able to qualify for the final and also reach the semi-finals is something unthinkable before this tournament. I am very proud of myself and look forward to the new challenges.”