For Zverev it was a gut-wrenching loss, only the second time he had lost from two sets up, the first being in the US Open final of 2020. And for the best part of three sets, the German was the better player, taking advantage of a passive, jaded-looking Medvedev to forge ahead.
Both men had spent more than 16 hours on court in their first five matches, but the pair proceeded to play out a series of marathon rallies, feeling each other out from the baseline.
While Medvedev began slowly, hitting five double-faults early on, Zverev was showing the kind of aggressive tennis that took him to a surprise win over Carlos Alcaraz in the previous round.
The German broke twice to lead 4-1, but Medvedev grabbed one of the breaks back in the next game. Slowly, Medvedev began to work over the Zverev forehand, breaking back in the 10th game, which included one 34-shot rally, only to then hand Zverev another break in the following game.
Medvedev had two chances to break but Zverev played a brilliant half-volley winner to end a 51-shot rally and earn set point, before clinching the set with a fine backhand volley.