WTA Championships Day 1 preview

Vera Zvonareva (pictured) rallied past Petra Kvitova in their last meeting. (Zumapress) The eight-player WTA Championships begin Tuesday at Sinan Erdem Arena

Vera Zvonareva (pictured) rallied past Petra Kvitova in their last meeting. (Zumapress)

The eight-player WTA Championships begin Tuesday at Sinan Erdem Arena in Istanbul, where the three women who have a shot at the year-end No. 1 ranking (Caroline Wozniacki, Maria Sharapova and Petra Kvitova) will be in action in round-robin play. Matches begin at 10 a.m. ET (5 p.m. local time).

Petra Kvitova vs. Vera Zvonareva: It's Attacker vs. Defender in this Red Group match, which features the biggest contrast in styles on the day. In their last meeting, Kvitova cruised to a 5-1 lead before dropping 11 of the next 12 games to lose in the Tokyo semifinals last month. Such is the volatility of the Wimbledon champion's game. Zvonareva leads the head-to-head 3-2, with all three wins coming on hardcourts (Kvitova's two wins were on clay).

The Russian forces a lot of balls back and her court coverage will put pressure on Kvitova to go for more on her shots (if that's even possible). Zvonareva may not hit the ball as hard, but when she plays well she can absorb pace and change direction of the ball at will.

With a 14-0 record on hardcourt/indoor surfaces this year, the tall lefty Kvitova has to have some confidence here. But she'll need to have her legs under her if she's going to reverse their Tokyo result.

Caroline Wozniacki vs. Agnieszka Radwanska: The top-ranked Wozniacki has won the last four meetings without dropping a set against her good friend. But has the Dane faced this Aga yet? Aga 2.0 has played the best tennis of her career this year, including an 11-1 fall with titles in Tokyo and Beijing. It seems as though all the little pieces that make her game work have come together.

This Red Group match could come down to something as simple (or complicated?) as belief: Does Radwanska truly believe she can pull off the upset? There's no reason she shouldn't. She has eight victories against top-10 opponents this year, tied for the Tour lead with Kvitova.

Maria Sharapova vs. Samantha Stosur: 9-0. The analysis of this White Group match should stop there. Stosur has never come close to beating Sharapova (she hasn't won a set or forced a tiebreak since 2006). But as the sports cliché goes, that's why they play the matches. The unknown factor here is Sharapova's ankle, which she twisted badly in Tokyo and has been rehabbing ever since. If the second-ranked Sharapova is hobbled or rusty, Stosur definitely has a chance.