New York, Sep 3 : World No. 1 and defending champion Aryna Sabalenka advanced to the semifinals of the US Open without having to play a point after her quarterfinal opponent, Marketa Vondrousova, withdrew with a knee injury.

"I am sorry to announce that I have to withdraw from my quarterfinal match this evening due to a knee injury," 2023 Wimbledon champion Marketa Vondrousova said in a statement.

"I tried my best to take the court today but during the warm-up I felt again my knee and after consultation with the tournament doctor decided not to risk aggravating the injury. I appreciate all the support this tournament and apologize to the fans who were looking forward to the match. I had an amazing time here in NY and can't wait to be back next year," she added

Sabalenka posted a message on her Instagram story to her opponent. "So sorry for Marketa after all she's been through. She has been playing amazing tennis and I know how badly this must hurt for her. Take care of yourself and I hope you can recover quickly."

Sabalenka, who is now one step closer to defending her US Open title, will face Jessica Pegula in the semis, a rematch of last year's final which Sabalenka won in straight sets.

The No. 4 seed and last year's runner-up Pegula reached the second major semifinal of her career with a 6-3, 6-3 defeat of Barbora Krejcikova in 1 hour and 26 minutes.

Pegula, 31, becomes just the second player among those who began their career in the Open Era to reach her first two Grand Slam semifinals after turning 30. She follows Flavia Pennetta, who made the 2013 US Open semifinals aged 31 and then became the champion in New York two years later.

/IANS