Daniil Medvedev did not take kindly to a question over the controversy surrounding Russian athletes at the Tokyo Olympics after he battled through sweltering conditions to reach the quarter-finals.

Medvedev beat Italy's Fabio Fognini 6-2 3-6 6-2 on Wednesday in a match that was paused for 10 minutes due to on-court temperatures reaching 31 degrees Celsius, with humidity then adding to that.

The world number two had to receive medical attention on two occasions before he prevailed to tee up a last-eight tie with Pablo Carreno Busta of Spain.

Top seed Novak Djokovic continued his march towards the medal matches with a routine win over Alejandro Davidovich Fokina, though in the doubles, Andy Murray's hopes of winning a historic fourth Olympic prize were shattered.

MEDVDEV'S TEMPER FRAYS IN THE HEAT

It had already been a stressful day for Medvedev. The 25-year-old replied "I can finish the match but I can die. If I die, are you going to be responsible?" when asked by chair umpire Carlos Ramos whether he could carry on playing against Fognini following two medical timeouts. 

Medvedev's temper then boiled over in the media mixed zone when he was questioned over the contentious nature of Russian athletes competing at the Games.

The Russian flag is not represented in Tokyo due to sanctions against the country for state-sponsored doping offences. Russia is suspended from competing in global sporting events for two years – a ban that was reduced from an initial four-year punishment. Instead, athletes are competing under the banner of the Russian Olympic Committee (ROC).

Medvedev was asked if he feels the Russian athletes are "carrying a stigma of cheaters".

Seemingly misunderstanding the question, Medvedev hardly held back in his reaction, saying: "That's the first time in my life I’m not gonna answer a question, man. And you should be embarrassed of yourself."

Before leaving the room, Medvedev subsequently told the press officer: "I think you should [remove] him from either the Olympic Games, either the tennis tournament. I don't wanna see him again in my interviews. Thanks."

MURRAY'S PARIS PARTICIPATION IN DOUBT

There was to be no fairytale title tilt for former world number one Murray. He won gold in the singles in London and Rio, and also managed a silver medal at the 2012 Games in the mixed doubles, but he and Joe Sailsbury suffered a defeat to Croatian pair Marin Cilic and Ivan Dodig in the quarter-finals.

The British pair won the first set but failed to make their advantage count, with Croatia's duo coming back to win 4-6 7-6 (7-2) 10-7.

Murray will be 37 by the time the Paris Games come around, and as he continues to carefully manage his return from hip surgery, the Scot could well have made his Olympic farewell.

"I don't know. I don't know if I'll get the opportunity to play [in the Olympics] again," he conceded.

"I love every minute of playing the Olympics. I wish that today would have gone differently. I had another chance with Joe to win a medal. We were so close and that is just disappointing. There was some stuff I wish I could have done at the end of the match to try and help out more. But yeah, very disappointing."

MIXED BAG FOR TSITSIPAS

While Medvedev, Djokovic and Alexander Zverev all progressed into the last eight in the singles, there was no place for Stefanos Tsitsipas, whose hopes were ended by Ugo Humbert.

The Greek world number four suffered a seemingly innocuous leg injury in the second set tie-break and failed to recover in the decider as Frenchman Humbert claimed the biggest win of his career.

However, Tsitsipas was swiftly back on court to play in the mixed doubles alongside partner Maria Sakkari, and the duo claimed a comfortable 6-3 6-4 victory over Canada's Gabriela Dabrowski and Felix Auger-Aliassime.

Asked after that win to discuss what went wrong in his earlier defeat, Tsitsipas replied: "I figured out a few things later during the match, like really, really late. 

"I think if I've had the same mindset or the same attitude, same vision that I had towards the very end of the match, I think things would have gone much, much smoother and better for me. It's something that I learned."

He also confirmed his injury was "nothing serious."

DJOKOVIC ON A ROLL

As expected, Djokovic is one win away from a shot at a medal in the singles, and he then followed up his victory over Davidovich Fokina by combining with Nina Stojanovic in the mixed doubles.

The Serbian pair beat Marcelo Melo and Luisa Stefani of Brazil 6-3 6-4 in just 70 minutes to book their place in the next round.

Djokovic will have the host nation against him in his next match, however, as he takes on Kei Nishikori, who is Japan's only hope of a singles medal after Naomi Osaka's exit.