Novak Djokovic confessed he was “right at the limit” of his physical and mental endurance beating Gaël Monfils in health-threatening heat on day four of the Australian Open and then made a heartfelt plea for the sport’s administrators to show more compassion for players.

“Our sport has become an industry,” he said after playing his part in entertaining the crowd in 39C heat on Rod Laver Arena for two hours and 45 minutes to put the Frenchman away in four sets (and six days after calling for more money from the slams, it might be recalled).

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He added: “It’s more business than a sport. At times I don’t like that. Of course we’re all blessed to have great financial compensation, great lives. I’m very grateful for that. At the same time, what is most important for us is our health and what happens after our careers, after you’re 30, 35. There are many players [who] can’t physically walk, run, jog, whatever. They’re struggling some way or another, health-wise or physiologically.

“You have to understand what the player goes through. There is no indication that we’re going to have any discussion for a shorter season or anything like it. We’re just adding events, official events, unofficial events. It feels, from a player’s perspective, that you’re always in a rush. You’re always obliged to play the mandatory events. You have always a big challenge to defend points because it affects everything. You’re always constantly, week after week, being part of that dynamic of our sport. At times it seem a bit too much.

“But it’s our choice at the same time. So I don’t want to sound ungrateful. On the contrary, I’m very grateful. But I also think that there should be some kind of rational conversation about rules that are maybe imposed or certain things that are concerning players’ well-being.”

As for the match, which he won 4-6, 6-3, 6-1, 6-3 after a decidedly shaky start, he said: “The conditions were brutal. We both struggled. Maybe he struggled a bit more at the end of the second set, entire third set. That’s where I managed to get on top of him. It was a big challenge for both of us to be able to finish the match.”

Facebook Twitter Pinterest Monfils feels the heat during the match. Photograph: Jonny Weeks/Guardian

Monfils, drained to the point of collapse, declared his sympathy for those left in the tournament as another heatwave began to wrap Melbourne in its warm embrace. “Good luck for the guys,” he said when told the temperature was expected to pass 42C on day five with more to come at the weekend. “Honestly, good luck for the guys.”

The Frenchman, however, would not endorse calls for the roof to be drawn across, although he suggested longer breaks between sets might be considered. “The fittest [will] win, and I think that is fair enough,” he said. “I’m telling you, I was dying on the court for 40 minutes. Yeah, we put our body at risk. Just be smart. No, I will never quit [but] if you have to give up, it’s nothing to be ashamed of.”

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Djokovic moves on, guarding a right elbow he admits is, “not 100%”. On Saturday he plays the 21st seed, Albert Ramos-Viñolas, who beat the American wildcard Tim Smyczek 6-4, 6-2, 7-6 (2). Djokovic’s main concern, alongside his endurance after six months out nursing an elbow back to reasonable health, will be his remodelled serve, which could not prevent 11 double faults.

“I can’t blame the conditions for my double-faults. It’s still that motion that I’m getting used to. Being rusty at the beginning is something that you can also expect. I just have to accept it, embrace it, obviously hope for a better day next match.”