Tokyo:Japan`s Kimiko Date Krumm celebrated her 40th birthday by beating Daniela Hantuchova to reach the Pan Pacific Open third round on Tuesday.
The former world number four won 2-6 6-0 4-0 after her Slovakian opponent retired with a shoulder injury.
"It`s a miracle I was able to stand up after yesterday`s match," Date Krumm, who stunned defending champion Maria Sharapova in the opening round, told reporters.
Second seed Vera Zvonareva overpowered Italian Sara Errani 6-3 6-3 to underline her title credentials at the $2 million tournament.
"I always believe if I play my best tennis I can beat anyone," said the Russian, who reached this year`s Wimbledon and U.S. Open finals. "I can`t wait for what`s next."
Top seed Caroline Wozniacki of Denmark crushed Hungarian Greta Arn 6-1 6-3 but fourth seed Samantha Stosur of Australia was eliminated 7-5 6-3 by Germany`s Julia Goerges and Russian Svetlana Kuznetsova also lost.
The 10th seed went down 6-3 7-5 to German Andrea Petkovic in another upset but 11th-seeded Frenchwoman Marion Bartoli avoided a potential banana skin by crushing Serb Ana Ivanovic 6-2 6-1.