Can anyone stop Serena in final four?
She clinched the year-end No. 1 ranking, but Victoria Azarenka wasn't sharp in dispatching Li Na 7-6 (4), 6-3 to reach the semifinals at the end-of-season championships in Istanbul. Up next for Vika is Maria Sharapova in a rematch of the Australian Open final.
Serena Williams, meanwhile, benefiting from a day off, tangles with Agnieszka Radwanska in a repeat of the finale at Wimbledon after the Pole outlasted Sara Errani 6-7 (6), 7-5, 6-4.
Here's a peek at Saturday's semis:
Read full story