American Serena Williams reached the semi-finals at the WTA Tour Championships in Istanbul on Thursday with what is fast becoming a routine defeat of world number one Victoria Azarenka.
The Wimbledon and U.S Open champion recorded a 6-4 6-4 win at the season-ending event, her fifth triumph over the Belarusian this year. Williams also owns an 11-1 record in their career head-to-heads.
The win was Williams’ third at the tournament and while she is guaranteed to top the round robin red group, Azarenka must now beat China’s Li Na on Friday to reach the last four.
The eighth-ranked Li ended German Angelique Kerber’s participation in the event with a 6-4 6-3 triumph.
Italy’s Sara Errani is also still in semi-final contention after a three-set win over Australian Samantha Stosur.
Errani faces a must-win match against Poland’s Agnieszka Radwanska if she is to join world number two Maria Sharapova in advancing from the white group.
Williams has won 12 of the 13 sets she has played with Azarenka this year. Her earlier wins over the 23-year-old came at Madrid, Wimbledon, the Olympics and the U.S Open.