"Push on," Cornes said.
"Lleyton Hewitt used to ask for his games to be scheduled in the middle of the day because that's his advantage.
"You come to Australia to play in the Australian Open, it's going to be hot so let's not have a whinge about it.
"The tough ones always get through and that's what I like about it. The fit players get an advantage, the ones that prepare themselves in the off-season.
"The players just need to toughen up and get on with it."
Australian Open's extreme heat policy, invoked in 2009 and 2014, could be enforced today with forecasts of 42C in Melbourne. That decision is made when the ambient temperature surpasses 40C and a wet-bulb (relative humidity) reading hits 32.5C.
Matches on outside courts are then halted and roofs closed on the three indoor-capable venues.
Here's what players and fans have to say.
Novak Djokovic said he was "right at the limit" of endurance in beating Gael Monfils in 39C, after their two hours and 45 minutes match. Djokovic struggled to draw breath at times.
The Serb, who has won the tournament six times, said: "There is a limit of being fit to play and being, I think, in danger to your health...it was right at the limit.
"Our sport has become an industry. 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...
"The conditions were brutal. We both struggled. It was a big challenge for both of us to be able to finish the match."
Gael Monfils was close to collapse, and sympathised with those left in the tournament. He told the chair umpire to forget the new rule that requires players to serve within 25 seconds between points. Monfils also suggested longer breaks between sets be considered.
"Good luck for the guys," he said of predicted 42C temperatures.
"The fittest will win, and I think that is fair enough.
"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.
"I got super dizzy...I think I had a small heat stroke for 40 minutes."
Roger Federer said he had experienced worse conditions in Melbourne.
"Sure I was watching the other players suffer but as long as nothing bad happens it's all good," he said, after playing in 30C."On a day like today, what do you do - do you stop all matches? Lucky guys on the big courts, do they get to play under the roof? Do the other guys get postponed to the next day and is that great?
"I honestly can't complain - the ATP is doing a nice job and there's a lot of physios and communication going on from officials towards us players."
Rafael Nadal: "I think it is a health issue. I like to, sometimes, play in heat. When it is too much, it becomes dangerous for our health. If the courts have roofs, why not put the roof on when the conditions are extreme?"
Juan Martin del Potro was heat-affected to the point it took him nearly three hours after his match with Karen Khachanov to meet the press.
Del Potro said: "It was really difficult to play...The temperature was too high for playing tennis. Also, if you saw the crowds, nobody was there watching under the sun."
The fans speak...
ESPN talked to Novak Djokovic fan Jessica Marintelli who said: "I'm from Perth, so I'm used to this...I want to be able to see him (Djokovic) from the best seat possible.
"These seats are hot; they are burning, and if you touch them it feels like your clothes are on fire.
"It was very, very hot. I put sunscreen on about six times and kept covering myself with cold water."
Another fan named Lynsey Stepan summed it up on Twitter saying "We don't get to see the best tennis...the players are just trying to survive."
