Sixth seed Elina Svitolina is safely through to the Australian Open quarter-finals after a see-sawing battle with American Madison Keys.

The Ukrainian overcame blisters and rebounded from a second-set hiccup to take out the fourth-round match on Margaret Court Arena 6-2 1-6 6-1 on Monday.

A marathon 16-minute third game in the final set proved decisive with Svitolina surviving seven break points before holding her serve and then running away with the win.