Overnight: Kyle Edmund outlasts Nikoloz Basilashvili as thermometer surpasses 40C

Britain’s Kyle Edmund secured an epic five-set victory over Nikoloz Basilashvili to reach the Australian Open fourth round for the first time in his career. The pair duelled for three-and-a-half hours in the Melbourne sun, and it was Edmund who prevailed 7-6(0) 3-6 4-6 6-0 7-5 as temperatures hit 42C on Show Court 2.

Third seed Grigor Dimitrov overcame 20-year-old Andrey Rublev in four sets to reach the last 16. The Bulgarian, who lost to Rublev in last year's US Open, struggled to hit top gear on the Rod Laver Arena, but persevered to win 6-3 4-6 6-4 6-4 and set up a fourth-round clash against either Nick Kyrgios or Jo-Wilfried Tsonga.

The Australian Open's extreme heat policy could be endangering the safety of players, according to France's Alize Cornet after she suffered dizzy spells during her third round match against Elise Mertens. Cornet slumped to the court after serving during the second set of her 7-5 6-4 defeat by Mertens at the Hisense Arena and needed a medical assessment as temperatures pushed past 40C (104F) at Melbourne Park.

The tournament's extreme heat policy, which involves closing the roofs of the stadiums and suspending outdoor matches, is invoked when the ambient temperature exceeds 40 and the wet bulb globe temperature index reading exceeds 32.5 degrees.

"Playing at this time was probably the worst time of the day," former world number 11 Cornet told reporters. "I kind of felt that I could faint at any moment."

Fourth seed Elina Svitolina ended 15-year-old Marta Kostyuk’s Australian Open run with a 6-2 6-2 victory to reach the fourth round for the first time in Melbourne. Svitolina proved too strong against fellow Ukrainian Kostyuk, who became the youngest player to win an Australian Open match in 22 years when she beat Peng Shuai in the first round.

Pablo Carreno Busta reached the fourth round for the first time after battling past big-serving Gilles Muller 7-6(4) 4-6 7-5 7-5. The Spaniard dug deep against Luxembourg’s finest, breaking in the 12th game of sets three and four to wrap up the win in three hours and 21 minutes.