(Transcript from World News Australia Radio)
Players at the Australian Open tennis tournament continue to struggle with searing temperatures in Melbourne.
Kristina Kukolja looks at some of what's in store on Day Four at Melbourne Park.
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Melbourne's heatwave has already seen some players retire from the Australian Open, and a dramatic drop in attendance by spectators.
On Day Four, the mercury is again forecast to pass 40 degrees.
Despite this, organisers have not invoked the tournament's extreme heat policy.
Chief Medical Officer, Doctor Tim Wood, says some players have experienced heat-related illness or discomfort, but none have so far required significant medical intervention.
But SBS Radio's Slovak program producer and tennis commentator Andrej Bucko believes the heat is causing serious problems on court.
"We have seen players retired, players vomiting on court, a lot of - especially women players - having cramps, and treatment for some ball kids and spectators. So, it did take some problems to realise that it is dangerous. Players' opinions vary. Federer is talking about professionalism, which is true. This tournament has been here for 102 years. They had the heat in the past and they just played with no roof. But we know how demanding the sport is now, and competitive tennis. So some cases could be dangerous. We'll wait and see."
One player to complain that organisers could be risking a tragedy in the extreme heat is last year's men's singles runner-up, Andy Murray of Britain.
On Thursday, he'll be on court again late in the day in a second round match against the unseeded Frenchman, Vincent Millot.
Other seeded players in the men's singles' second round on Day Four will be Roger Federer of Switzerland, Juan Martin Del Potro of Argentina, and France's Jo Wilfried Tsonga.
Frenchman Gilles Simon will meet former men's top-ten Marin Cilic of Croatia, who is playing his first Grand Slam tournament since a doping ban forced his withdrawal from Wimbledon last year.
One of three Australians in action in the singles competition will be wild card entrant Thanasi Kokkinakis, who faces a monumental task to get into the third round.
He's up against the men's World Number One player Rafael Nadal of Spain.
Nadal, whose injury-related seven-month absence from competition included the 2013 Australian Open, says the time away has given him a fresh perspective.
"It's true that when you have a period of time outside of the competition and you are back the mental part is a little bit fresher than ever. It seems like everything is new again. One way there are bad feelings because you are going back and you always have problems when you are back. But for another part it is great when the feelings are great to come back to the stadiums to play in full stadiums, the best stadiums in the world. It's something that you get used to, but when you are out for a while you really missed a lot and you appreciate more when you are back."
Reigning champion Victoria Azarenka of Belarus, Russia's third seed Maria Sharapova, and Poland's Caroline Wozniacki continue their campaigns for the women's singles title.
13th seed Sloane Stephens will also be in action in round two on Thursday.
Stephens produced a major upset when she eliminated fellow American, 17-Grand-Slam-champion Serena Williams, to reach the semi-finals in Melbourne in 2013.
To progress to the third round this year, she first needs to outplay the unseeded Croat, Ajla Tomljanovic.
Stephens says she's looking forward to playing the 20-year-old.
"I've known her for a while. We both went to Evert (Chris Evert Tennis Academy) together, and I've know here for a long time. I think she is the same age as me, so I think it will be a good match. I know she's just coming back. I know she was a little sick or had an injury. I haven't seen her play in a while so I have to do my research, but I think it will be a good match. I'm excited to get back on the court."
