Australian Open officials are taking drastic measures as the season-opening grand slam faces the prospect of attempting to play on through potentially some of the hottest recorded temperatures in Melbourne's history.
The mercury is predicted to soar to 45C in Melbourne on Tuesday, with organisers already implementing a raft of schedule changes and safety rules to battle the extreme heat.
It could be the hottest day in Melbourne ever, after the city suffered through 46.4-degree heat in 2009, the highest temperature recorded for the Victorian capital.
Women's world No.1 Aryna Sabalenka takes on Iva Jovic in the opening match on Rod Laver Arena, where the roof is likely to be open at the 11.30am start.
Crucially, that will also allow play to begin on outdoor courts under the current heat policy.
But suspensions are certain later in the day as officials monitor the Heat Stress Scale (HSS) - the system implemented in 2019 - amid concerns over player and spectator safety.
Four climate factors - air temperature, radiant heat, humidity and wind speed - are measured from various locations at Melbourne Park to determine the HSS measure.
Play on the outside courts and roof closures on the main arenas will follow the Open's extreme heat protocols.
Sabalenka's quarter-final clash with Jovic is followed by a last-eight battle between men's seeds Alexander Zverev and Learner Tien.
Women's seeds Coco Gauff and Elina Svitolina open the night session from 7pm, before home hope Alex de Minaur takes on career slam-hunting Carlos Alcaraz.
De Minaur, the sixth seed, isn't bothered by the forecast temperatures for his blockbuster clash with the Spanish world No.1.
"I mean, I'm Aussie. I don't mind the heat," the 26-year-old said.
"I have said it since day one. That's just what I have grown up with, and I'm ready for these types of conditions.
"I assume the roof will be closed. I don't know for certain, but if the heat rule is into effect, it's going to make it a little bit of an indoor match.
"Hey, it is what it is. I mean, once I rock up on Tuesday and I walk on court, you just deal with whatever's in front of you."
Alcaraz, meanwhile, conceded "you've got to get used to everything" as he puts the forecast heat out of his mind in preparation for de Minaur.
"Whatever it is, I just will be ready," Alcaraz said.
"I will be focused. I will try not to think about it.
"I will try not to affect my game at all, and I think that's it."
Svitolina has reached the quarter-finals for the second straight year and is eyeing a first appearance in the Open's last four.
The Ukrainian hopes her later timeslot will grant some relief from the heat.
"It's of course better to play in the evening. It's much nicer," Svitolina said.
"Of course, still the ball is flying quite a bit because of the heat, but yeah, it's going to be fine either way."
Officials on Monday confirmed a series of measures to combat the heat, including allowing ground pass ticket holders access to Margaret Court Arena.
Ballkids will have reduced rotations, increased recovery times, and additional relief squads.
And the AO wheelchair championships have been postponed and will start on Wednesday.
It comes after officials were forced to implement extreme heat protocols on Saturday, when play was suspended on outdoor courts and roofs were closed on the major venues.
