NEW YORK - Britain's Jack Draper powered into the US Open semifinal on Wednesday with a straight-sets drubbing of a hobbled Alex de Minaur, while Czech Karolina Muchova battled a "bug" but still took down Brazilian Beatriz Haddad Maia on the Arthur Ashe Stadium.

The brutal toll of five rounds of tennis on New York's hard courts was apparent as all four players struggled through injury or illness that delayed both matches at times.

Draper, the 25th seed who has yet to drop a set at Flushing Meadows this year, topped the Australian 10th seed 6-3 7-5 6-2 and became the first British man to reach the US Open's final four since 2012 when Andy Murray claimed the year's final major.

"I think I played a solid match. I feel the best fitness-wise I've been in a long, long time and I think that's where Alex has sort of got me in the past," Draper said in his on-court interview.

"I also think he was struggling a little bit today with something, which may have helped me," he said.

De Minaur battled to find his range from the start and was broken early, setting the tone for the match as he racked up the unforced errors while Draper served well.

The second set was briefly interrupted when both players had injury concerns as De Minaur, who withdrew from Wimbledon with a hip injury, moved gingerly and Draper took a timeout to have his right thigh strapped.

When play resumed, De Minaur broke to level the set at 4-4 only to see Draper break in the 11th game before consolidating to seize a 2-0 lead in the match.

Draper's power and precision in the third set wore down De Minaur, dealing him defeat in a Grand Slam quarterfinal for the fourth time in his career.

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"The way he can spread the court, being a lefty and really move you around the court, it takes a toll on the body. Accumulation of matches takes a toll, as well," De Minaur said.

In the day's early match, Muchova, in only her sixth tournament back after suffering a wrist injury at the 2023 US Open, beat Haddad Maia 6-1 6-4 to reach the tournament's last four for a second consecutive year.

Muchova was sharp in the first set as she grabbed a 4-0 double break lead, held to love and, after Haddad Maia finally got on the board, closed out the opening set on serve.

Haddad Maia improved in the second set and the players exchanged breaks before Muchova, after having the physio and doctor at her chair, held to reach 5-3 before taking advantage of new balls and sealing victory on serve with an ace.

"I think I played good in the key points, meaning when I had a breakpoint or I was serving for a game, I always pulled out a good shot, I think," Muchova said. "I'm happy that I managed it in two sets again."

"I'm fighting (a) bug a little bit. I'm a little sick. I hope it didn't disturb anyone," she said.

Haddad Maia, the first Brazilian woman to make the US Open quarterfinal since Maria Bueno in 1968, also required medical attention late in the match when she appeared to be having difficulty breathing.

In the night session, top seeded Iga Swiatek will look to reach her seventh Grand Slam semifinal as she takes on sixth seeded American Jessica Pegula, who has not advanced beyond a Grand Slam quarterfinal in six tries.

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Fifth seed Daniil Medvedev, who won at Flushing Meadows in 2021, and top seeded Jannik Sinner, the Australian Open champion, will battle it out in a Grand Slam for the third time this year.