The world's top tennis players are psyching themselves up for a scorching week at the Australian Open with temperatures set to soar above 40 Celsius in Melbourne.
Temperatures are forecast to reach 42 Celsius (107 Fahrenheit) on Tuesday and remain around those levels until a cooler change next weekend.
The Australian Open has an Extreme Heat Policy, introduced in 1998, involving a complex calculation of air temperature, humidity, wind and medical advice, and enforced at the discretion of referees.
It has only occasionally been invoked, with play halted or the roof on the main stadiums closed and air conditioning turned on. But the conditions have to be severe.
Players, many of whom have experienced Melbourne's extreme summers, will be given ice vests and packs, while a good number arrived in Melbourne early to acclimatise.
However, world number three Maria Sharapova warned: "I don't think anyone can prepare themselves for that type of heat.
"I think it's tough to train on a very high level in that type of heat.
"When you try to put in that effort, that maximum effort to give as an athlete, it's pretty difficult for a longer period of time."
Sharapova remains rueful about her 2007 three-setter played in searing heat against France's Camille Pin, after which she called the conditions "inhuman".
"How could I forget," she said, when asked about that match. "I didn't feel too good after."
She added: "You're not really thinking about tennis, you're trying to really keep your mind focused on maybe keeping the points a little bit shorter.
"Obviously, the longer they go, the worse it is for both of you out there."
Novak Djokovic has also been through the grinder in Melbourne, retiring in the 2009 quarter-finals against Andy Roddick due to heat exhaustion when defending his title.
"I know how tough it is. But it's the same for myself and my opponent so you have to adjust to it," he said.
World number one Serena Williams, aiming to match Chris Evert and Martina Navratilova with 18 Grand Slam titles, is not looking forward to the hot days, but said she could cope.
"I've been training my whole life in the heat. I think I'm pretty used to it," said the Florida-based American.
"I mean, obviously the heat in Melbourne is just completely different than any other heat.
"But it's okay. I just got to be ready to play under any circumstances."
Andy Murray, returning from back surgery, is another who trained in Florida during the off-season, but he said Australian conditions were a different matter.
"I mean, it helps," said the Scot. "But the difference between 32 degrees or whatever in Florida and 40, it's a huge difference.
"It feels very different on the court. The court gets so hot, the air is extremely hot as well."
Not everyone is perturbed, with defending women's champion Victoria Azarenka saying she was even looking forward to the extreme conditions.
"I've been here playing for, what, last eight years. It's not a new thing to play in the heat. I actually enjoy that," she said.
"I mean, not all the time probably, but it's nice to get some sun."
The hottest Australian Open on record was in 2009 when the average daily temperature was 34.7 Celsius