Caroline Wozniacki and Elina Svitolina march on but sweltering Melbourne heat causes more problems

Australian Open 2018: Alize Cornet claimed the heat was “dangerous for the health of the player” after having to send for the doctor during her defeat by Belgium’s Elise Mertens

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The Australian Open will review its extreme heat policy after players struggled here for the second day in succession in temperatures of more than 40C. Although a characteristic Melbourne “cool change” saw the temperature drop sharply late in the afternoon, those players who were on court earlier in the day had to deal with brutal conditions.

Alize Cornet claimed that the heat was “very dangerous for the health of the player” after having to send for the doctor during her 7-5, 6-4 defeat by Belgium’s Elise Mertens. The 27-year-old Frenchwoman suffered with dizziness and at one stage collapsed to the floor in Hisense Arena.

A combination of heat and humidity readings are used to determine whether conditions are too extreme for play to continue. If pre-determined thresholds are reached, the roofs on the three main show courts are shut and matches on the outside courts suspended.

Despite today’s intense heat, the humidity readings were low enough for organisers not to apply their extreme heat policy, though they admitted they had come close to doing so and said they would review the protocol after the tournament.

Cornet complained that the tournament’s criteria for halting matches needed to be lowered. “Playing in this condition is of course very dangerous for the health of the player,” she said.

“The limit of not playing the match is really high. I think this limit should be a little lower because playing in this condition is not nice for anyone.”

Cornet was one of several players who suffered in the heat. Croatia’s Petra Martic, who beat Thailand’s Luksika Kumkhum 6-3, 3-6, 7-5, took pain killers to deal with blisters on her feet which she said had been caused by the heat coming off the court surface in Rod Laver Arena.

Cornet collapsed to the floor during her match on Hisense Arena (Getty)

“These conditions are really, really tough and there are some girls that don’t handle it well,” Martic said. “They are having tough times out there.”

Rafael Nadal, who had the advantage of much cooler weather as he raced to a 6-1, 6-3, 6-1 victory over Damir Dzumhur, agreed that playing in 40C heat “is not safe enough sometimes” and said the conditions were “very, very tough”.

He added: “Sometimes it’s too much and can become a little bit dangerous for health. It's not nice to see players suffering that much on court.

“But there is one positive thing: there was no humidity, so it was dry. That made a big difference. In my opinion the conditions are tougher, for example, in Rio de Janeiro than here because the humidity there is crazy and the heat is almost the same.”

Jelena Ostapenko was sent packing by Anett Kontaveit (Getty)

Jelena Ostapenko became the latest top name to go out of the tournament when she was beaten 6-3, 1-6, 6-3 by Anett Kontaveit. The French Open champion took an injury time-out to have her left thigh strapped at the end of the first set but seemed to have turned the match around when she took the second set for the loss of only one game.

Kontaveit, however, broke serve in the seventh game of the decider and again in the ninth to secure one of the biggest wins of her career. The 22-year-old Estonian, who had never won a match here before this week, is through to the last 16 of a Grand Slam tournament for the second time, having last done so at the US Open three years ago.

Caroline Wozniacki, the world No 2, eased into the last 16 with a 6-4, 6-3 victory over the Dutchwoman Kiki Bertens in the last match of the day in Rod Laver Arena.

Marta Kostyuk, who at 15 was the youngest singles player to reach the third round of a Grand Slam tournament for 21 years, was beaten 6-2, 6-2 in just 59 minutes by her fellow Ukrainian, Elina Svitolina.

Although Kostyuk said she could have played better she also paid credit to her opponent. “How much do you have to pay Svitolina to have a one-hour lesson?” Kostyuk said. “I got it for free.”