NEW ⁠YORK, Sept 9 (Reuters) - Karen Khachanov reached the U.S. Open semi-finals ⁠on Wednesday when Alexander Blockx retired trailing 6-2 7-5 3-2, as ‌the Russian reached the final-four stage in Flushing Meadows for the first time since 2022.

Blockx, who became the first Belgian man to reach the U.S. Open quarter-finals, was ​already carrying a rib injury into the ⁠match and was visibly hampered ⁠by further physical issues. He wore a brace on his right ankle ⁠and ‌had his thigh wrapped, with the 21-year-old also calling for the trainer during the contest.

The 28th-seeded Blockx battled on despite ⁠his discomfort but was unable to match Khachanov as ​the 30-year-old continued ‌his resurgence in New York, before eventually calling it a day ⁠after one ​hour and 38 minutes.

"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."

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.

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 last eight.

He ‌will face either top seed Alexander Zverev ​or Dutchman Botic van de Zandschulp in the semi-finals.

(Reporting by Janina Nuno Rios in New York; Editing by Stephen Coates)