Top-seeded Samantha Stosur was a second-round winner Wednesday at the HP Open.
The Australian Stosur rallied past Virginie Razzano of France by a 1-6, 6-2, 6-4 margin at Utsubo Tennis Center.
Stosur captured the Osaka title in 2009 and was last year's runner-up here to France's Marion Bartoli.
The 2011 U.S. Open champion Stosur has yet to win a tournament since her breakthrough Grand Slam title last year at Flushing Meadows. She was the runner-up in Doha back in February after a first-round flameout at the Australian Open and has yet to reach another final.
After a quarterfinal appearance at this year's U.S. Open, Stosur reached the semifinals in Tokyo to start the Asian swing before a loss in her first match last week in Beijing.
Stosur will next face Jamie Hampton in the quarterfinals. The American beat Thai wild card Tamarine Tanasugarn, the 2010 Osaka champ, 7-5, 7-5.
Other second-round wins came from Taiwan's Kai-Chen Chang and Japan's own Misaki Doi. Chang took out Aussie Casey Dellacqua 7-6 (7-4), 6-3, while Doi recorded a 6-3, 6-2 victory over Russian qualifier Olga Puchkova.
This week's winner will earn a first prize of $37,000.