Defending champion Victoria Azarenka beat injured American Jamie Hampton 6-4, 4-6, 6-2 to reach the fourth round of the Australian Open.

Azarenka maintained her streak of advancing to the fourth round of every Grand Slam since the 2011 U.S. Open

The match featured 12 service breaks.

Hampton called for the trainer for treatment on her lower back just before successfully serving for the second set. But she appeared to be in so much pain on a number of occasions during the third that she had tears in her eyes.

The top-ranked Azarenka broke Hampton in the sixth game of the final set, with the American wincing in pain on almost every shot.

Hampton had triple break point in the following game, but couldn't convert and Azarenka clinched the match in the next game.