Istanbul: Maria Sharapova upset World No.1 Victoria Azarenka in straight sets to book an encounter with Serena Williams in Sunday`s WTA Championships final.
Sharapova beat Azarenka 6-4, 6-2 Saturday after earning two early breaks in the first set and taking control in the second when Azarenka began to struggle with a problem affecting her right thigh.
"When you`re playing the World No.1, you have to be ready for every shot - you have to run because the point can keep going and going," Sharapova said on the WTA website.
"I`d lost to Victoria the last few times, so I`m really happy I put myself in the semifinals to play against her and try to improve that - I was hoping to have a better result, and I`m really happy I did today."
The Belarusian leads Sharapova 7-5 in head-to-head meetings.
Despite the defeat, the Belarusian will hold the World No. 1 spot at the end of the season after winning six titles including her first Grand Slam tournament at the Australian Open.