Daniil Medvedev defeated fellow Russian Andrey Rublev 6-4, 6-3, 6-4 in scorching conditions Wednesday to reach his fourth US Open semi-final and set up a possible meeting with defending champion Carlos Alcaraz.

Third seed Medvedev, the 2021 US Open champion, rallied from a break down in all three sets as he condemned a frustrated Rublev to a ninth straight Grand Slam quarter-final loss.

Medvedev will play Alcaraz or German 12th seed Alexander Zverev for a place in Sunday's final after an energy-sapping duel against the eighth-ranked Rublev as the temperature hit 95 degrees Fahrenheit (35 degrees Celsius) in New York.

At one point during the third set Medvedev muttered to a nearby TV camera "one player is going to die and they're going to see" as he grabbed a towel mid-game.

"The conditions were brutal. The only good thing is that both players suffer, so it's tough for both of us," Medvedev said after the 2hr 48min encounter, during which the extreme heat policy was in effect.

"At the end of the first set I kind of couldn't see the ball anymore. I kind of just played with sensations."

Medvedev overturned a 3-0 defeat in the opening set in a repeat of their 2020 quarter-final here.

He dropped serve twice in the second set but hit back for a 4-3 lead before summoning the trainer complaining of breathing difficulties.

Medvedev resisted three break points the very next game and broke once more to claim a two-set lead.

He then used the time between sets to cool down off court.

"I couldn't wait to go to the cold shower, but the thing about that is when you come out either you can't move because your body blocks or you feel better," said Medvedev.

"I just thought I don't care, I'm just going to do it, but I didn't need to, so I am going to do it now."

Rublev twice surged in front in the third set only for Medvedev to respond on both occasions, sealing victory in a marathon final game courtesy of his nine break of the match.

mw/rcw