World No 1 Ashleigh Barty and Belinda Bencic both advanced to the semifinals after contrasting victories at the WTA Finals in China on Thursday.
Barty progressed from the round-robin stage with a crushing 6-4, 6-2 win over Petra Kvitova in one hour and 28 minutes at the Shenzhen Bay Sports Centre. Bencic prevailed 7-5, 1-0 in 61 minutes after late replacement Kiki Bertens retired ill.
Bertens received medical attention after the opening game of the second set, where her blood pressure and pulse were checked, before becoming the second player in the tournament to retire mid-match after Bianca Andreescu withdrew against Karolina Pliskova on Wednesday.
