Unseeded Karolina Muchova moved into the US Open quarter-finals as she upset fifth seed Jasmine Paolini on Monday.

Muchova, who made the semi-finals in New York in 2023, recovered from being 3-1 down in the opening set to secure a 6-3 6-3 victory over the Italian.

Paolini, 28, has had a great 2024, reaching the final of both the French Open and Wimbledon. But she struggled to deal with her Czech opponent’s serve as Muchova lost just five points when serving.

“I was a little bit nervous from the start so I was trying to get my shots to feel the ball,” said the 28-year-old. “Jasmine Paolini is an incredible player. I’m just really happy it’s worked again for me here.”

Muchova lost to Poland’s Iga Swiatek in the 2023 French Open final and reached the final four of the US Open three months later, losing to eventual champion Coco Gauff.

However, a wrist injury kept her out of action for 10 months but she is now finding her best form again.

“This was my worst and most serious injury I would say but I love the sport,” added Muchova. “I’m really grateful to all the people that helped me and yeah, I’m just a really happy kid now.”

She will next play either former world number one Caroline Wozniacki or 22nd seed Beatriz Haddad Maia.

American sixth seed Jessica Pegula also reached the last eight as she opened play on the main show court with a 6-4 6-2 win over Russia’s Diana Shnaider.

Swiatek aims to continue dominant form

The top seed is in action in the evening session on Arthur Ashe Stadium as Iga Swiatek, who is yet to drop a set in the tournament, goes up against 16th seed Liudmila Samsonova at 00:00 BST.

The Polish world number one has already won five Grand Slam titles at the age of 23 and is looking for her second success in the United States after winning the 2022 US Open.