Victoria Azarenka books last WTA Championships semi-final place

Victoria Azarenka has claimed the last semi-final spot at the WTA Championships in Istanbul with a straight-sets victory over Li Na.

The 7-6 6-3 triumph has also confirmed that the Belarusian will end the year at the top of the world rankings.

Despite a tricky opening set, Azarenka was far more dominant in the second to beat the Chinese world number eight.

Azarenka will now battle it out with Maria Sharapova for a place in Sunday's final.