Bent over in exhaustion before serving. Resting on his racket between points. Grasping for a rubber tube blowing cool air next to his seat on changeovers. Two medical timeouts and one visit from a trainer. Daniil Medvedev was struggling so much with the suffocating heat and humidity at the Ariake Tennis Park on Wednesday that at one point the chair umpire, Carlos Ramos, asked him if he could continue playing.

"I can finish the match but I can die," Medvedev replied.

"If I die, are you going to be responsible?"

Still, the second-seeded Medvedev produced a 6-2, 3-6, 6-2 win over Fabio Fognini of Italy to reach the quarterfinals at the Tokyo Olympics.

The ROC player is going to need some time to recover from this one, though, and it raises questions over why organisers did not grant requests earlier in the tournament from Medvedev and other players including top-ranked Novak Djokovic to move all of the tennis matches at the Games to the evening.

After some rain a day earlier, the temperature rose to 88 degrees F (31 degrees C) but the heat index made it feel like 99 degrees F (37 degrees C).

Medvedev received medical treatment for an apparent abdominal problem while leading 5-2 in the opening set but then held his serve in the next game to close it out. He then took another medical timeout while trailing 4-3 in the second.

Visibly suffering, Medvedev took his time between points, which drew protests from Fognini.

Both players were allowed to leave the court for 10 minutes between the second and third sets with an extreme heat rule in effect.

After holding for a 5-2 lead in the third, Medvedev received yet more medical treatment when a trainer came out onto the court and massaged his left arm and thigh.

Fognini slammed his racket onto the court in disgust when the match was over, then picked the racket up and placed it in a court-side trash can.

Medvedev if he's up to it will next face sixth-seeded Pablo Carreno Busta of Spain for a spot in the medal rounds. Carreno Busta beat Dominik Koepfer of Germany 7-6 (7), 6-3.

In the women's tournament, fourth-seeded Elina Svitolina of Ukraine beat Camila Giorgi of Italy 6-4, 6-4 to reach the semifinals.