Melbourne - A ball boy collapsed and water bottles melted on court as the world's top tennis players struggled in extreme heat which soared towards record levels at the Australian Open on Tuesday.
Players draped themselves in ice towels and guzzled water on the changeovers with the thermometer hitting 40.5 Celsius (104.9 Fahrenheit) by early afternoon.
"It felt pretty hot, like you're dancing in a frying pan or something like that," said defending women's champion Victoria Azarenka. "I don't think anybody wants to go outdoors right now."
Temperatures are forecast to peak at 43 Celsius, shy of Melbourne's all-time January high of 45.6, at the start of a heatwave which is expected to be among the most severe on record.
Daniel Gimeno-Traver helped a ball boy to his chair after he collapsed during the Spaniard's four-set loss to Milos Raonic.
And former women's world number one Caroline Wozniacki said when she put her water bottle down on court, the bottom started melting.
"Geez, it feels hot out there," said Wozniacki, who headed straight for an ice bath after her win over Lourdes Dominguez Lino. "It feels like I was sweating in a sauna or something.
"It's really tough... I was just trying to take the ice towel as much as I could and try not to think about the heat, like I'm in Alaska or something."
Officials are keeping a close eye on the heat and humidity -- and for signs of exhaustion among players -- as they weigh up whether to call off play and close the roofs on the centre and second court.
Tuesday's expected peak of 43 Celsius is shy of Melbourne's January record of 45.6 Celsius, which came during the notorious Black Friday bushfires of 1936.
High temperatures are expected to remain for most of the week, in similar conditions to the 2009 Black Saturday bushfire disaster which killed 173 and injured hundreds more.
Emergency officials announced a blanket fire ban across Victoria and warned of extreme temperatures in parts of the state.
At Melbourne Park, unshaded public seating areas outside the stadiums lay largely empty as fans stayed out of the sun.
Volunteers handed out sunscreen to spectators who entered the venue wearing sombreros, umbrella hats and sunglasses. A young girl frolicked in a fountain to stay cool.
The Australian Open is no stranger to extreme heat with many incidences in the past, but few occasions when play has been suspended.
In 2009, the hottest edition on record with an average daily temperature of 34.7 Celsius, reigning champion Novak Djokovic pulled out of his quarter-final with Andy Roddick, citing heat exhaustion.
And in 2007, women's star Maria Sharapova called the conditions "inhuman" after playing a gruelling three-setter against France's Camille Pin.
Officials have sought to play down any health risks, pointing out that no player has ever died from dehydration on a tennis court.