Samantha Stosur has continued her memorable season of firsts with a brilliant straight-sets victory over world No.1 Caroline Wozniacki at the WTA Championships in Doha.
In a powerhouse display, Stosur plundered five aces and countless other unreturnable serves and forehand winners in a 6-4 6-3 triumph that has Australia's fifth seed just one set away from clinching a semi-final berth in her maiden singles appearance at the prestigious season-ending event.
Having upset the then top-ranked Serena Williams in the French Open quarter-finals, Stosur is now the first player this year to conquer two world No.1s.
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The Queenslander can guarantee her place in the last four with success over Russian seventh seed Elena Dementieva in her final round-robin match on Thursday (1am Friday AEDT).
Stosur saved four match points in a thrilling three-set win over Dementieva in their most recent encounter at this year's US Open in New York.
But even a three-set defeat would probably be enough for Stosur to progress.
Wozniacki had the chance to secure the year-end top ranking with victory on Wednesday, but Stosur's firepower instead reduced the smiling Dane to a nervous wreck.
After burying her racquet into the Doha hard court in frustration midway through the first set and then seeking some courtside advice from her father-coach Piotr, Wozniacki had finally had enough after one hour, 27 minutes.
"Any time you beat the world No.1, it's a good thing," Stosur said.
"I thought I played really well today and I'm pleased to get through.
"It's just so exciting to be here. You get to the end of the year and you've just got to give everything you've got and it's all coming together."
Stosur has already won two season-ending doubles titles in 2005-06 with American Lisa Raymond, but now has her sights firmly on winning the coveted singles crown.
For Wozniacki, the champagne remains on ice after second seed Vera Zvonareva joined Stosur with a two-from-two record to remain a mathematical chance of snatching the year-end No.1 ranking from the 20-year-old Dane.
Zvonareva beat Belarussian Victoria Azarenka 7-6 (7-4) 6-4 on Wednesday, after accounting for Serb Jelena Jankovic in straight sets on Tuesday.
And two-time champion Kim Clijsters launched her bid for a third season-ending title with a 6-2 6-3 win over Jankovic.
Her second successive straight-sets defeat all but eliminated Jankovic from semi-finals reckoning.
