Williams and Sharapova into final

Serena Williams and Maria Sharapova will face each other in the final of the WTA Championships in Istanbul. Williams, the American world number three, booked her place in Sunday's final with an emphatic 6-2 6-1 win over Agnieszka Radwanska in 61 minutes. Sharapova, the world number two from Russia, had to work much harder before overpowering world number one Victoria Azarenka 6-4 6-2 in her semi-final. The match featured a sixth game in the second set that lasted 15 minutes.