Victoria Azarenka has won her opening match at the WTA Championships in Istanbul with a dramatic three-set victory over Angelique Kerber.
Both players dropped serve once in the opening set before Kerber came from 2-6 down to clinch a remarkable tie-break 13-11.
The German looked on course to defeating the world number one when she earned herself two match points, but Azarenka forced the tie-break and squared the match with a 7-2 triumph.
Azarenka and Kerber broke each other twice more in the deciding set, only for the Belarusian to break once more and close out the contest 6-4.
