Defending champion Aryna Sabalenka was given a free passage through to the US Open semi-finals after Marketa Vondrousova withdrew through injury.

Less than two hours before they were supposed to meet in the night session on Arthur Ashe Stadium, the tournament announced Vondrousova was not able to take to the court.

The Czech’s withdrawal means there will be a rematch of last year’s final in the last four, with Sabalenka taking on fourth seed Jessica Pegula.

It is a bitter blow for former Wimbledon champion Vondrousova, who has struggled with injury throughout her career but had been on a great run in New York after beating Jasmine Paolini and Elena Rybakina.

In a statement via the organisers, the 26-year-old Czech said: “I am sorry to announce that I have to withdraw from my quarterfinal match this evening due to a knee injury.

“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.”

Writing on Instagram, Sabalenka said: “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. Love Aryna.”

Earlier, Pegula made it back to the semi-finals in convincing fashion by beating another Czech former Wimbledon champion, Barbora Krejcikova, 6-3 6-3.

Pegula had struggled prior to arriving at Flushing Meadows and put her change of mindset down to a visit to an escape room and drinks with friends following a poor practice session the week before the tournament.

She proved too solid for Krejcikova, who dramatically saved eight match points in her previous contest against Taylor Townsend but served poorly here and paid the price.

“We all saw what she (Krejcikova) did against Taylor so I was happy that we’re done,” said Pegula.

“It’s crazy to look now and think I’m really comfortable playing on big courts with the craziest crowds against the big players. Ten years ago I never thought I’d be good at this but I guess I am.

“I feel like I can always come back to the fact that I can figure it out in the end, and that always hits me in the toughest moments of the year.

“It’s not fun to go out there and stress yourself out and be worried about how you’re playing every second of the day. I definitely did that for a few weeks, but I guess I got over it.”

Pegula made the better start, quickly moving into a 3-0 lead, and it was the same story in the second set.

Krejcikova briefly threatened a comeback when Pegula missed chances to lead 5-1 and the Czech responded with two games in a row but two double faults in the final game rather summed up her day.

On facing Sabalenka again, Pegula said: “I think it would be cool to be able to get revenge, obviously.”