Maria Sharapova defeated Australia’s Sam Stosur to finish first in her group at the WTA Championships in Istanbul on Friday.

Sharapova extended her head-to-head record against Stosur to 11-2 after a 6-0, 6-3 win in which Stosur won just five points in the first set.

The Russian won all three matches of the group stage of the $4.9 million season-ending event and will now play a semifinal against the winner of Friday’s encounter between world No. 1 Victoria Azarenka and China’s Li Na.

Stosur, who had arrived in Turkey as first alternate before stepping in when Petra Kvitova fell ill, lost both of her matches at the tournament.

She finishes the season at No. 9 in the WTA rankings after a title-free 2012.