(CNN) -- The 2013 tennis season may only be in its fledgling stages but already the heat is well and truly on for those preparing for the year's first major.
As the great and good on the men's and women's circuits fine tune their game ahead of the Australian Open that starts in Melbourne on Monday, they are having to contend with stifling temperatures in Sydney.
According to the Australia Bureau of Meteorology, Monday was the hottest day in the country since records began over 100 years ago with an average temperature of 40.3 degrees.
Officials in New South Wales have warned of a "catastrophic" fire threat as strong winds combine with the heat to increase the danger of bushfires spreading out of control.
Players had to battle heat that reached 41.4 deg in Sydney, with world No. 4 Agnieszka Radwanska claiming it was "too hot" to play and that officials should have halted proceedings under their extreme heat policy.
But the Pole, along with the other players scheduled on Tuesday, battled through the searing sunshine with the help of regular breaks, ice towels and gallons of liquid.
"I think this is too hot to play tennis," Radwanska told reporters at a press conference. "Even for players, for ball kids, for even the people sitting out there, I think it's just too hot."
One saving grace for Radwanska was her quick 6-4 6-3 victory over Japan's Kimiko Date-Krumm which meant she was only on court for 68 minutes.
Russia's Svetlana Kuznetsova battled through to a 7-6 1-6 6-2 victory over former world No. 1 Caroline Wozniacki, though both players benefited from a heat break before contesting the deciding set.
Kuznetsova told reporters: "I think it shows you one more time how tough the tennis is right now. How players have to be fit to play in the hot conditions, the windy conditions. We're like iron women almost.
"It was very hot out there. In the second set the heat definitely disturbed me a lot. But the break really helped me before the third set."
The 2011 French Open champion, Li Na of China, was quoted as saying by AFP that she felt like she was "playing in a sauna."
Germany's Angelique Kerber triumphed 6-2 7-5 over Russian qualifier Galina Voskoboeva who took a medical time out because of the extreme heat.
Kerber: "It was unbelievably hot. Usually I practice before my matches, 30 to 35 minutes, today it was just 10 or 15 minutes because I couldn't play more. It's tough to play in these conditions.
"I was trying to focus on the next point and not thinking about the heat, the sun and the weather. The whole match was tough from the first point. I'm happy I won in two sets."
Temperatures were due to cool off for Wednesday's play but by the end of the week the thermometer will be back up to 37 degrees in Melbourne, according to Jenny Harrison from the CNN Weather Center.
She told CNN's World Sport show: "We do see this every couple of years but this is record-breaking heat. Monday has been confirmed as the hottest day across Australia since records began.
"It looks as if Tuesday, once we get the stats in, could be the hottest day and outdo Monday.
"What has happened in the last few hours is a front has come through across the south east of Australia. In literally an hour the temperature in Sydney has dropped more than 10 degrees.
"Melbourne is cooler than that as the front went through there first. But in Melbourne by the end of the week the temperature is going to rise again, getting well above average."