Players know to expect some pretty warm weather when they come to play at the Australian Open in the middle of summer Down Under.

But Thursday saw the mercury rise to a dangerously high level in Melbourne, peaking at 39 degrees.

While the ambient heat was uncomfortable enough for those merely spectating, on-court temperatures sweltered around 70 degrees to raise serious concerns over player safety.

Gael Monfils, for example, displayed signs of heat exhaustion during his four-set loss to Novak Djokovic, leaving many wondering why tournament officials refrained from enacting the Extreme Heat Policy.

Players who thought they were lucky to avoid the court today will be sorely mistaken, with Melbourne expecting even hotter conditions on Friday.

Rafael Nadal is one of the unlucky individuals due to contest his third-round match in 42-degree heat tomorrow, and he hasn’t shied away from voicing his displeasure.

Speaking after his victory over Leonardo Mayer, the Spaniard suggested all roofs should be closed at Melbourne Park for the sake of protecting players.

NADAL'S REQUEST

“Well, only thing that I hope, if is extreme conditions, I hope the organisation puts the roof. That’s all,” he said, per the Metro.

"I think is a health issue. Even I like sometimes play with hot. When is too much, it becomes dangerous for the health.

“I would not like to see here retirements. Conditions that create a bad show for the crowd. The crowd is suffering too there. In the courts that we have the roof, why not put the roof when the conditions are so extreme?

“By the way, I’m going to practise indoors tomorrow.”

Nadal’s logic makes perfect sense, but according to tournament officials, there’s an equally legitimate reason to let the sun continue beating down.

TOURNAMENT OFFICIALS RESPOND

In a statement released following widespread calls to cover courts wherever possible, authorities said: “The health of our players is of paramount concern, but we need to be consistent with the outside courts so some don’t get an unfair advantage.

“The referee will initiate the Extreme Heat Policy once the ambient temperature exceeds 40C & the Wet Bulb index (WBGT) exceeds 32.5C.

“The health of our players is of paramount concern to us, and we are constantly monitoring conditions. Let’s hope it cools down!”

They make a good point. Imagine how players cooking away on outside courts would feel knowing Nadal and Damir Dzumhur are doing battle in the air-conditioned comfort of Rod Laver Arena.

Not exactly a level playing field, Rafa.