Li Na to play Petra Kvitova in semifinals of WTA Championships on Saturday . Chinese star will become Asia 's highest-ranked player if she beats the Czech . Jelena Jankovic will face world No . 1 Maria Sharapova for first time since Wimbledon final last year. ` I think I can learn a lot from these little things to prevent maybe some of the injuries . Serbian goes through despite losing to already-eliminated Sara Errani .
Li Na to play Petra Kvitova in semifinals of WTA Championships on Saturday . Chinese star will become Asia 's highest-ranked player if she beats the Czech . Jelena Jankovic will face world No . 1 Maria Sharapova for first time since Wimbledon final last year. Serbian goes through despite losing to already-eliminated Sara Errani .