Victoria Azarenka has beaten Samantha Stosur in three sets to make it through to the semi-finals of the Rome Masters.

The Australian Open champion took the opening set 6-4, but she was brushed aside 6-1 in the second by the battling Stosur.

Both players struggled to hold serve in the third, though it was the world number three who eventually came through 6-3.

Waiting for Azarenka in the last four is Italian seventh seed Sara Errani.