Vera Zvonareva of Russia won the first four games of the third set, then held on for a 5-7, 6-4, 6-4 win over fifth-seeded Ana Ivanovic of Serbia in the semifinals of the Mercury Insurance Open Saturday night. The top-seeded and third-ranked Zvonareva, who won a hard court event last week in Azerbaijan, will play Agnieszka Radwanska after the Polish player beat Andrea Petkovic of Germany 4-6, 6-0, 6-4. Zvonareva raised her game substantially to win the first four games of the third set after losing a tough first set, then needing seven set points to finish off the second. But trailing 5-1 in the third, Ivanovic came back to win three straight games and force Zvonareva to serve for the match. The Russian, who had a match point on her serve at 5-3, finally closed the match when Ivanovic netted a forehand. Zvonareva, the two-time Grand Slam finalist, reached her third final this season and increased her winning streak to a career-high nine matches. She forced a third set after squandering six set points before finally hitting a backhand winner to nail down the second set. The Russian broke Ivanovic's serve in the first game of the match. The pair then held serve until Ivanovic broke back in the 10th game to even the set at 5-all. After Ivanovic held serve, she won the set when Zvonareva double faulted on set point. Radwanska, seemingly still bothered by a right shoulder injury, rebounded from losing the first set by winning 10 straight games to win the second set and jump ahead 4-0 in the third. Petkovic revealed she was sick to her stomach when she took the court, and that it got worse as the match wore on. Petkovic eventually sprinted off the court during the second set to go to the bathroom so she could vomit. Radwanska took advantage of the situation and raised her game while Petkovic dealt with her issue. Radwanska reached her first championship match since she lost here last year to Russia's Svetlana Kuznetsova. She will be seeking for her first title since 2008 and her fifth overall.