Li Na to play Petra Kvitova in final of WTA Championships on Saturday . Chinese star will become Asia 's highest - ranked player if she beats the Czech . Jelena Lara will face world No . 1 Serena Williams in other last - four match . 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 Serena Williams in other last-four clash . Serbian goes through despite losing to already-eliminated Sara Errani .