US Open champion Naomi Osaka is a step closer to back-to-back grand slam crowns after scrapping her way into the quarter-finals at Melbourne Park.

The world No.4 battled back from a set down to beat Latvian 13th seed Anastasija Sevastova 4-6 6-3 6-4 on Monday to reach the Australian Open’s last eight for the first time.

Osaka will face Elina Svitolina for a semi-final berth after the Ukrainian sixth seed ousted American Madison Keys 6-2 1-6 6-1 in their fourth-round affair.