An Extreme Heat Policy was introduced last year which gives umpires the power, in certain situations, to suspend matches.

However, that can only come into force on the outside courts. Federer and Djokovic go head-to-head on Rod Laver Arena so it is possible they may have to play their match with the roof closed and the air con switched on.

The Australian Open has come up with a Heat Stress Scale which factors in the ‘radiant heat, air temperature, humidity and wind speed’.

A rating is then produced between one to five which gives an indication of the relevant action to take.

If one is shown then it is deemed ‘temperate playing conditions’. For two the recommendation is to ‘increase hydration’.

‘Apply cooling strategies’ is advised when the figure ticks over three.

Serious action is taken when the rating rises to four – as it did for the start of Ashleigh Barty’s semi-final against Sofia Kenin.

Temperatures hit 38 degrees as the world No 1 took on the American with a place in the final up for grabs.

That meant the players were guaranteed a 10-minute break at the end of the second set.

Federer and Djokovic would get a 10-minute break at the end of the third set if the rating stays the same as their match will be best-of-five sets.

“That is probably the worst situation [for Djokovic], or probably the best situation for Roger to have a chance against Novak,” Wilander, who hosts Eurosport’s Game, Schett & Mats show, said.

“And if he had hung in there then it will have been Rafa [Nadal]’s best chance to win the tournament.

“I don’t think it is going to last until Sunday but it is good for Roger in the semis. He likes it when it is hot and the ball spins.

“For Roger to get to the final this is a good set-up – if that’s what you’re looking for. A really good set-up. The tennis Gods timed that one perfectly.”