( CNN ) -- Australian Sam Stosur continued her giant-killing habit at the French Open by beating top seed Serena Williams to book a place in the final four . Stosur , who eased past four-time champion Justine Henin in the previous round , triumphed 6-2 6-7 8-6 in two hours and 24 minutes at Roland Garros . The seventh seed will play Jelena Jankovic in the semifinal after the Serb beat Yaroslava Shvedova , from Kazakhstan , 7-5 6-4 . It means there will be a brand new Grand Slam winner by the end of the week , with none of the final four yet to break their duck at the major championships . The match went with serve in the opening set until Stosur won five games in a row with some scintillating tennis , to clinch the first 6-2 . Stosur continued strongly in the second to go 5-3 up before Williams rallied and leveled at 5-5 . The top seed went on to take it on a tie-break . In a tense deciding set breaks were exchanged early on before Williams edged ahead to lead 5-4 . Stosur held her nerve to survive a match point and go on to take the game . With the match locked at 6-6 Stosur rediscovered her blistering form , and fired two winners past Williams to secure a crucial break of serve . Stosur needed no second invitation to wrap up the match on her serve and seal a place in the last four . SI.com : Most impressive women 's feat of year . `` It 's two great matches back-to-back for me , which is fantastic , '' Stosur told reporters . `` It 's not over yet . Now I 'm in the semis and I want to definitely try and keep going . I made it to this point last year . If I can try and go another set further , then that would be great . '' She will meet Jelena Jankovic after the Serb made light work of the unseeded Yaroslava Shvedova . The other semifinal sees Italian Francesca Schiavone face Elena Dementieva .
Sam Stosur defeats top seed Serena Williams in the French Open quarterfinal . Stosur triumphs 6-2 6-7 8-6 in two hours and 24 minutes to reach semis . Australian will play Jelena Jankovic in last four . Jankovic beat Yaroslava Shvedova in straight sets .