Ukrainian fourth seed Elina Svitolina outclassed 15-year-old compatriot Marta Kostyuk to reach the Australian Open fourth round.

Svitolina, 23, won 6-2 6-2 in 59 minutes against world number 521 Kostyuk.

The youngest player since 1997 to reach the third round of a Grand Slam, Kostyuk was aiming to be the youngest since 1996 to progress to the last 16.

Svitolina will play world number 130 Denisa Allertova in round four.

“It was sad that I was playing a Ukrainian girl,” said Svitolina. “It’s always difficult playing someone from your own country, but I’m happy that I’m still alive in this tournament.

“She’s a great fighter, she fought right until the end and has a great future.”

The Ukrainian pair’s match was played in 40C heat on Rod Laver Arena while France’s Alize Cornet had her blood pressure taken by a doctor during her defeat by Elise Mertens on the Hisense Arena.

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