Petra Victoria Azarenka beats Vera Zvonareva to make semis at WTA Championships . Radwanska , from Poland , currently occupies second spot after she saved three match points to beat Russia 's Vera Zvonareva 1-6 6-2 7-5 . Kvitova wins 6 -4 6-2 to knock world No.1 Woznaicki out of tournament . Kvitova joins Kvitova in the final four after beating China 's Li Na . Agnieszka Radwanska beats Caroline Wozniacki to keep hopes of semi berth alive .
Petra Victoria Azarenka beats Vera Zvonareva to make semis at WTA Championships . Kvitova wins 6 -4 6-2 to knock world No.1 Woznaicki out of tournament . Kvitova joins Kvitova in the final four after beating China 's Li Na . Agnieszka Radwanska beats Caroline Wozniacki to keep hopes of semi berth alive .