World number one Ashleigh Barty said she produced some of her best tennis this year as she battled into the China Open semi-finals Friday with a gutsy victory over Petra Kvitova.

The Australian came from a set down to win 4-6, 6-4, 6-3 and plays Ukraine’s Elina Svitolina or Kiki Bertens of the Netherlands in the last four in Beijing.

“From my opinion, that was one of the highest-quality matches I played all year,” said the 23-year-old, the reigning French Open champion.

“Petra always has a way of bringing out the best in me, she really does.

“From both of us, I think the level was incredible. 

“Regardless of winning or losing, I think I’d be sitting here with the exact same perspective, kind of the same feeling of the match afterwards.”

This was the sixth meeting between Barty and two-time Wimbledon champion Kvitova, with the former winning only one of her previous encounters against the Czech.

Barty, who had strapping on her left calf, was under the cosh immediately in the deciding set after seventh-ranked Kvitova broke her first service game.

But Barty grabbed the break back and, with the clock ticking past two hours on court, broke Kvitova again for a decisive 5-3 lead.