Australian world number one Ashleigh Barty reached the semi-finals of the WTA Finals with a straight-set win over Czech sixth seed Petra Kvitova.

Barty, 23, won 6-4 6-2 to eliminate the two-time Wimbledon champion from the season-ending event in Shenzhen.

Swiss seventh seed Belinda Bencic or Dutch alternate Kiki Bertens, who replaced the injured Naomi Osaka, will also progress from the Red Group.

Whoever wins their final group match on Thursday will reach the last four.

French Open champion Barty, competing in the WTA Finals singles for the first time after a stunning year, is assured of top spot after recovering from Tuesday’s defeat against Bertens with a dominant win over an out-of-sorts Kvitova.

Barty edged the key moments in the opening set, breaking for a 3-2 lead and saving break points in each of her next two service games, then ran away with the second as Kvitova began to tire.

“I felt I executed really well and knew I had to come out and play aggressively,” said Barty, who has won her past three matches against Kvitova.

“I had a few early break points against me and I played them really well. It was important to keep my nose in front.”

Bencic or Bertens will battle for second place in the group later on Thursday, with the winner facing defending champion Elina Svitolina in the semi-finals.

Ukraine’s Svitolina was the first player to make the last four by beating Wimbledon champion Simona Halep in the Purple Group on Wednesday.

Romanian Halep plays Czech Karolina Pliskova in their final round-robin match on Friday, with Barty awaiting the winner in Saturday’s semi-finals.

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