Maria Sharapova battles the heat during a changeover on Tuesday

Melbourne: Maria Sharapova and David Nalbandian lambasted the Australian Open’s extreme heat policy on Tuesday after they struggled with the stifling conditions during their first-round matches.

With the mercury just short of 40°C, all unstarted matches were suspended on the outside courts for several hours. But under the rules, players already on court have to finish their matches.

Organisers kickstart their extreme heat plans when the thermometers pass 35° and when the Wet Bulb Globe Temperature, a combination of ambient air temperature and humidity, exceeds 28°.

“It’s inhuman to play three hours in that kind of heat,” Sharapova said following her 6-3, 4-6, 9-7 win over France’s Camille Pin.

“I don’t think our bodies were made to do that. When it’s that hot your mind doesn’t work properly,” added the Russian, who looked dazed during the closing stages of the match.

Play was restricted to the two main courts — Rod Laver Arena and Vodafone Arena — where action was only possible because of the retractable roofs. These can only be closed between matches. Temperatures later exceeded 50 degrees.

Nalbandian was extremely critical. “The thing I didn’t understand is why they didn’t call the match (off) after 40-something degrees.”

France’s Julien Benneteau even lost consciousness after his five-set defeat to Paul Capdeville. “Several times I thought about quitting but I pushed myself to my limits...,” he said.

Meanwhile, Police flooded the Open on Tuesday to prevent further clashes between Serb and Croat fans after ethnic violence marred action on Monday. Police ejected 150 people after the melee.

Fans on Tuesday had to pass through metal detectors as security searched for weapons amid threats from some of those thrown out to return for more confrontation with their rivals. (Agencies)