World number one Iga Swiatek crashed out of the US Open as American Jessica Pegula finally ended her grand slam quarter-final hoodoo at the seventh attempt.

Swiatek had eyes on winning a second title in New York to cement her position as the top player in the women’s game, but she was off-colour in a 6-1 6-4 defeat.

Pegula must have thought she was never going to get into a grand slam semi-final having lost her first six last-eight ties, going back to 2021, but she put that right in front of a partisan home crowd on Arthur Ashe.

She was solid and looked after her own business but, in truth, her victory was as much about Swiatek’s erratic display as 41 of Pegula’s 65 points came as a result of unforced errors.

The sixth seed will not be complaining and she hopes beating the Pole will be a good omen for the coming days as on the previous three occasions she has beaten Swiatek she went on to win the tournament.

“I have been here so many freaking times,” she said on court. “I just kept losing, but to great players, players who went on to win the tournament.

“Finally, finally I can say I’m a grand slam semi-finalist.

“To do it against the number one in the world is crazy, I knew I could do it, I was able to take advantage of some things she wasn’t doing very well early on and that carried through.”

Waiting in the semi-final is Karolina Muchova, who overcame illness to continue her assault on the tournament.

The Czech received medical treatment and had to leave the court four times for comfort breaks, but she still did the business beating Beatriz Haddad Maia 6-1 6-4 to reach the last four for the second successive year.

She is still in the early stages of a comeback from a serious injury, where she spent 10 months on the sidelines following wrist surgery, only returning in June.

And she is making up for lost time in New York, looking as good as anyone left in the draw and still yet to drop a set in the tournament.

A tough test lies ahead in the shape of world number one Iga Swiatek or home favourite Jessica Pegula next for Muchova, but she will be confident going into the match, providing her health concerns clear up.

“A little weird match I have to say, I have some problems I don’t want to comment on if that’s OK,” she said on the court.

“I am happy to manage it, running to the bathroom and back, sorry if it disturbed anyone but I had no other choice.

“I am really happy to be in the semi-final, I wouldn’t have said that before the tournament. Every round gets more difficult and I am sure it will be a difficult match.”