Alexander Zverev swept past Botic van de Zandschulp to reach the US Open semi-finals, while Karen Khachanov advanced after an injured Alexander Blockx retired.

Alexander Zverev took another big step towards a second Grand Slam title by beating Dutchman Botic van de Zandschulp 6-2 7-5 6-1 on Wednesday to reach the US Open semi-finals, setting up a showdown with Karen Khachanov.

Khachanov had earlier advanced when Belgian Alexander Blockx retired trailing 6-2 7-5 3-2, sending the Russian into the last four at Flushing Meadows for the first time since 2022.

Zverev, the 29-year-old French Open champion, got off to a slow start in his campaign in New York but has steadily found his range as the tournament has progressed.

“I think you saw in the first two rounds, I really didn’t play well,” Zverev said.

“In other tournaments I would be out in the first round, but here I can fight back and play best of five sets, play 4-1/2 hours. I’ve started playing better throughout the tournament and I’m definitely happy to be in the semi-finals here.”

The German has reached the semi-finals at all four majors this year and is the only Grand Slam winner left standing in the men’s draw.

“I don’t take it for granted at all,” Zverev said.

“I know it can change in a heartbeat in tennis. I think confidence is something that is incredibly important but also can go away quite quickly.”

Zverev was far from steady on serve early on at Arthur Ashe Stadium, coughing up five double faults in an erratic start, but Van de Zandschulp leaked forehand errors to allow the top seed to break in the fifth game and then take the opening set.

Van de Zandschulp regrouped in the second and came close to levelling the contest, but Zverev absorbed the pressure and reeled off three games in a row towards the end of the set as the momentum swung firmly in the German’s favour.

Zverev, the 2020 US Open runner-up, fired an overhead smash to break early in the third and cruised home from there to reach his third semi-final in New York.

With 23 Grand Slam match wins this year, Zverev also surpassed Boris Becker’s German men’s record of 22 from 1989.

Injured Blockx forced to retire

Khachanov’s route into the semi-finals was more straightforward after Blockx’s injury problems brought their quarter-final to a premature end after one hour and 38 minutes.

Blockx, who became the first Belgian man to reach the US Open quarter-finals, was already carrying a rib injury into the match and was visibly hampered by further physical problems.

The 21-year-old wore a brace on his right ankle and had his thigh wrapped, while also calling for the trainer during the contest.

The 28th-seeded Belgian battled on despite his discomfort but was unable to match Khachanov before eventually deciding he could not continue.

Blockx, who upset fifth seed Flavio Cobolli in the third round, had already hinted at his physical problems after admitting he came close to retiring during his fourth-round match against Francisco Cerundolo.

“Today my body just gave up,” Blockx told reporters.

“I had it really difficult physically already. Against Francisco, I was on the verge of retiring, and today just kept getting worse.

“I was still feeling my rib a lot. My leg. Then in the second set, I blocked a nerve in my back, which yeah, was even worse to move.”

World number 50 Khachanov will return to a Grand Slam semi-final for the first time since reaching the last four at the Australian Open in 2023.

“I was preparing really well for that match up, it’s not easy because I feel I was dominating then I felt he was struggling more and more,” Khachanov said on court.

“He was suffering, but I wanted to keep the energy there. I wish him a speedy recovery but I’m super happy I’m in the semis.”

The former world number eight, who had not played a major with a ranking this low since 2017, had already knocked out third seed Felix Auger-Aliassime and 14th seed Learner Tien on his way to the quarter-finals.

Khachanov will now face Zverev in a rematch of their gold-medal showdown at the Tokyo Olympics in 2021, adding another chapter to their rivalry with a place in the US Open final at stake.