Serena Williams continued her good run of form over Maria Sharapova to beat the Russian in straight sets and win the final of the WTA Championships in Istanbul.

Williams has now won 10 of the 12 meetings between two of the biggest names on the women's tour and has now avenged her 2004 defeat to Sharapova in the final of the same tournament by taking a 6-4 6-3 win.

The 31-year-old American also lost in the Wimbledon final showdown with Sharapova in the same year but never looked in trouble as she won inside an hour and a half in Turkey.

The success saw Williams win her third WTA Championships title and was her seventh title of a highly successful 2012.

There was better news for Russia in the double's tournament as qualifiers Maria Kirilenko and Nadia Petrova completed a weekend of upsets to beat the second seeds Andrea Hlavackova and Lucie Hradecka.