ISTANBUL (AP) — Victoria Azarenka wrapped up the season-ending No. 1 position in the world by beating Li Na 7-6 (4), 6-3 on Friday in the WTA Championships.
Azarenka secured a spot in the semifinals and will next play Maria Sharapova.
"It's kind of difficult to believe that a little girl from Belarus is on that list," said Azarenka, from Belarus. "It's really incredible achievement. When I started to play tennis I had this big picture in my head that I want to be there. Back then it's so far away. It's like pretty much touching the sky.
"I'm here sitting kind of in the sky, so it's really incredible feeling."
Agnieszka Radwanska advanced to the semifinals when she edged Sara Errani 6-7 (6), 7-5, 6-4 in a match that lasted nearly 3 1/2 hours. The fourth-ranked Radwanska will play Serena Williams on Saturday.
Sharapova swept past Sam Stosur 6-0, 6-3 on the final day of round-robin play but Azarenka's win means that the Russian will not be able to wrest the No. 1 ranking form her.
Azarenka won the Australian Open in January and had been ranked No. 1 for most of the year, except for a brief period after Sharapova won the French Open.
Sharapova had already qualified for the semifinals of the elite, eight-woman event and has won all three of her round-robin matches.
The Russian rolled through the first set, allowing Stosur only five points. Stosur was an alternate who replaced defending champion Petra Kvitova, who withdrew because of illness.