In a high-quality match, Djokovic levelled the match at 1-1 after winning a thrilling second set tie-break, before Medvedev stunned everyone by retiring.
“It’s the second time in my life I retired like this with a pulled muscle,” said Medvedev. “So here, on the second point of the tie-break, I felt a little bit [of a] strange pop in my adductor.
“I first thought maybe it is cramp and after the point I was like, `No, probably not a cramp'.
“If I won, I would not play the final. I was like, ‘okay, I just try to hit some shots’. If I manage to win, well I cannot do anything, I will retire. If I lose, congrats to Novak, he’s still in great shape.”
US Open highlights: Kyrgios outclasses Medvedev, Jabeur and Tomljanovic power through
Should Medvedev not play for the rest of this month, his place at the Nitto ATP Finals in Turin, which take place from November 13 to November 20, would not be guaranteed.
He’s currently fifth in the rankings, 695 points ahead of Felix Auger-Aliassime, who is currently the first player not in a qualifying spot for the tournament.
ATP 500 events in Switzerland and Austria take place on the week beginning October 24, with the Paris Masters starting on October 31, where up to 1000 points can be won.