Victoria Azarenka has booked her spot in the quarter-finals of the US Open with a 4-6 6-3 6-4 victory over Ana Ivanovic.

It was Ivanovic who secured an early break in the first set before holding to move 3-0 ahead. Azarenka did manage to break back at 5-3, but another break for Ivanovic allowed the Serbian to claim the opener.

Incredibly, the first five games of the second set all brought breaks of serve, but three of those went to Azarenka, before another break at 3-5 allowed the Belarusian to move level on terms at one-set all.

Both players continued to struggle in the early stages of the third and final set, with four breaks in the opening five service games.

It was a similar story in the latter stages, but successive breaks for Azarenka booked her spot in the next round of the competition.