Second-seeded Zheng Jie of China was among the winners Tuesday in the first round at the HP Open, while former French Open champ Francesca Schiavone retired during her opening match.
Zheng rallied for a 4-6, 7-5, 6-4 victory over Spain's Maria Jose Martinez Sanchez, while Schiavone -- the fourth seed and 2009 Osaka runner-up -- was trailing, 6-4, 2-1, in the second set against Russian qualifier Olga Puchkova before calling it quits because of a right wrist injury.
Anabel Medina Garrigues of Spain, South Africa's Chanelle Scheepers and rising British star Laura Robson were all seeded winners on Tuesday, but fifth-seeded Yaroslava Shvedova of Kazakhstan was upended by 2010 Osaka champ Tamarine Tanasugarn of Thailand.
Tanasugarn, given a wild card entry into the tournament, rolled to a 6-3, 6-2 victory and will face American Jamie Hampton in the second round on Wednesday.
The sixth-seeded Garrigues dropped the first set of her match against Italy's Camila Giorgi before storming back to claim a 3-6, 6-2, 6-2 triumph. Scheepers, the seventh seed, thumped American Alexa Glatch, 6-4, 6-1, while the eighth-seeded Robson dumped Greek veteran Eleni Daniilidou, 6-4, 6-2.
Other winners Tuesday included French veteran Virginie Razzano, Croatia's Mirjana Lucic and Chinese qualifier Zhou Yi-Miao. Razzano cruised to a 6-3, 6-3 win over Thai qualifier Nudnida Luangnam to earn a second-round matchup on Wednesday against top-seeded Samantha Stosur.
This week's winner will earn a first prize of $37,000.