Organisers on Monday reassured players their safety was paramount at the Australian Open, saying no one had ever died from extreme heat at a tennis tournament while warning of the dangers of over-drinking. (Ferrer, Wawrinka in round 2)
Temperatures were forecast to hover above 40C (104F) over the next four days but tournament officials said plans were in place to look after the players in the sweltering conditions. (Kimiko out in first round)
"Tennis, as a sport, is relatively low risk for major heat problems compared to football and continuous running events," the tournament's chief medical officer Tim Wood said.
"Certainly in the next four days the players will have plenty of chance to acclimatise. (Li Na through to second round)
"The body does put in measures that assist in coping with the heat, so if anything, the players will acclimatise with playing in the heat. (Venus loses in first round)
"They might actually get better, particularly with the 48 hours' rest between matches."
Wood said there has never been anybody who has died from dehydration on a tennis court.
"We have had players almost die from drinking too much. So the danger is over-drinking, not under-drinking and becoming dehydrated," he said.
"Given the length of time tennis matches generally go for and the sweat rate of most normal, healthy athletes, they won't get to a state where they get too critically dehydrated."
Wood said the players know what is going to happen with the weather for the next four days at the Melbourne tournament before a cool change arrives at the weekend.
"They do get an advice sheet that's sent out to them before the tournament starts on the fact that Melbourne's weather is rather variable," he said.
"We can get 16C to 42C degrees at any time. We give them advice on how best to prepare for playing under those conditions."
Tournament referee Wayne McKewen said the implementation of the event's extreme heat policy was at his discretion and he would take expert advice before stopping play.
"There is no set number. We have Tim Wood advising me as to the conditions. Bob Leighton, our meteorologist, is on?site. We have a dedicated weather station at Melbourne Park," McKewen said.
"So we are getting specific temperatures at Melbourne Park."
The Open's Extreme Heat Policy, introduced in 1998, involves a complex calculation of air temperature, humidity, wind and medical advice, and enforced at the discretion of the tournament referee.
It has only occasionally been invoked, with play halted or the roof on the main stadiums closed and air conditioning turned on.
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.