China’s Zheng Qinwen reached the semi-finals of the WTA Finals in Riyadh after claiming an impressive 6-1, 6-1 win over Italian fourth seed Jasmine Paolini. In her WTA Finals debut, the 22-year-old became the youngest player to reach the semi-finals since Petra Kvitova in 2011.

The seventh seed fired 12 aces in a dominant performance, recording her 30th win from 34 matches since Wimbledon. “It’s one of the best performances I had during this year,” she said on court. “Really good percentage of first serves. I enjoyed a lot tonight to play here.”

Zheng won 77% of her first-serve points as she became the second Chinese woman to reach the last four of the WTA Finals after Li Na. “[This was] almost 11 years ago. I’m proud I could make it,” Zheng said. “I didn’t know what would happen when I came here because it’s my first time. I just told myself to enjoy. Especially because I’m in a really difficult group.”

The Paris Olympic champion finished second in the purple round-robin group behind top seed Aryna Sabalenka.

World No 2 Iga Swiatek will play Daria Kasatkina on Thursday in her must-win match to stay in the hunt for a spot in the WTA Finals semi-finals after Jessica Pegula withdrew from the tournament with a knee injury. The sixth-seeded American pulled out, the WTA said on Wednesday, after a 6-3, 6-3 defeat by the Wimbledon champion Barbora Krejcikova on Tuesday ended her chances of qualifying for the last four.

Pegula has been replaced by first alternate and world No 9 Kasatkina, who will face Swiatek in her final match in the orange group. The Pole will look to rebound from her 6-3, 6-4 loss to Coco Gauff and also needs the already-qualified American to beat Krejcikova to advance.