Brilliant Barty's last four spot in the bag as Kvitova beaten
World No.1 Ashleigh Barty marched into the last-four of the WTA Tour finals with a straight-sets win over Petra Kvitova in Shenzhen.
Barty, who has already ensured she will finish the year on top of the rankings, produced a business-like performance to see off her Czech rival 6-4 6-2 in just one-and-a-half hours.
It was Barty's third consecutive win over Kvitova, having lost each of their first four meetings.
Barty said: "It's a challenge that I love and thrive on. I think each time I've played Petra, I've become a better player having learned from what happened through that match."
Barty repeatedly rose to the occasion at the crucial moments, breaking Kvitova for the first time in the fifth game of the match, then resisting four break points on her own serve in order to wrap up the opening set.
Kvitova collapsed in the opening game of the second set as Barty pressed home her advantage, ensuring another break with some outstanding shot-play.
Barty would not face a break point in the set and a second break enabled her to secure victory and guarantee first position in the tournament's Red Group.
Belinda Bencic joined Barty in the last-four after Kiki Bertens was forced to retire midway through their match due to illness. Bertens trailed 7-5 1-0 before she withdrew, citing stomach problems and dizziness, allowing Bencic to advance as the Red Group runner-up.