Two-time Wimbledon champion Petra Kvitova, competing in only her second tournament since her playing hand was injured in a knife attack at her home, has advanced to the semifinals at the Birmingham Classic.

Benefiting from the injury retirement of Italian Camila Giorgi, Australia’s Ashleigh Barty also made it through to the final four of the Wimbledon warm-up, although compatriot Daria Gavrilova wasn’t so fortunate, falling to Lucie Safarova in three sets.

Friday’s other winner was former French Open champion Garbine Muguruza who got through after unseeded American CoCo Vandeweghe fell and hurt her ankle.

In defeating Kristina Mladenovic 6-4 7-6 (5), Kvitova struck the ball solidly on both sides, moved well and made bold forays to the net.

However she double-faulted twice when she was trying to close out the match at 5-3 in the second set. Mladenovic evened the score and led 3-1 in the tiebreaker.

She rescued herself with two pieces of good luck.

First, Mladenovic double-faulted going for 4-1 in the tiebreak and when she was serving at match point down at 5-6 Kvitova’s widish-looking service return took a net cord, lurched into court and fell dead.

“I am sorry for what happened at match point but I am very happy to win,” Kvitova said.

“She is very highly ranked (12) and for me it is only the second tournament in my comeback. I was very happy with my performance.”

Kvitova next plays fellow Czech and friend since childhood, Safarova, who had her own drama, saving match points for the second time this week.

She recovered from 5-3 down in the final set to beat Gavrilova 6-7 (4) 6-3 7-6 (5).

Safarova saved two match points against third-seeded Dominika Cibulkova in the first round and three against Gavrilova in a contest so full of entertaining rallies the women received a prolonged standing ovation.

The tournament’s other Grand Slam winner, Muguruza, reached the semifinals for only her third time this year and the first on grass since reaching the final of Wimbledon nearly two years ago.

It happened abruptly when Vandeweghe shook hands just three points into the final set.

Muguruza won 4-6 6-4 30-love, though she took pleasure in again having achieved a good rhythm on a surface which is not the most natural for her.

“I came here early and I have put in the hours and I feel I’m doing something good because I am winning,” she said. “But to be honest I didn’t even realise she was going to retire.”

Vandeweghe injured a foot in her opening match which, she said, contributed to her tumble in the second set.

Muguruza next plays Barty, who was leading Giorgi 5-2 when she became the second injury retirement on the day.