Tokyo, Japan (My Sportsbook) - Olympic gold medalist Elena Dementieva and U.S. Open runner-up Caroline Wozniacki caught the upset bug in second-round play Tuesday at the $2 million Pan Pacific Open. Former world No. 1 stars Jelena Jankovic and Maria Sharapova managed to move into the third round on Day 3.

One day after the tournament's top-two seeds -- Dinara Safina and Venus Williams -- were dealt early exits, the third-seeded Dementieva of Russia was handed a 6-2, 6-7 (3-7), 6-1 defeat at the hands of Ukrainian qualifier Kateryna Bondarenko, while a fourth-seeded Wozniacki was trailing Canadian Aleksandra Wozniak 0-5 in the first set when the Dane retired due to a viral illness on the hardcourts at Ariake Colosseum. Dementieva captured this event in 2006.

Two more Russians were upset Tuesday, as sixth-seeded Vera Zvonareva was bested by compatriot Alisa Kleybanova, 3-6, 6-4, 6-2, and No. 13 seed Nadia Petrova fell in straight sets to Magdalena Rybarikova of Slovakia, 6-2, 6-2.

An unseeded Sharapova, who titled here in 2005, contributed a mild upset by blasting 12th-seeded Aussie Samantha Stosur 6-0, 6-1.

There was some semblance of normalcy in the second round. A seventh-seeded Jankovic snuck past big-serving German Sabine Lisicki 6-3, 4-6, 6-2; No. 8 seed Victoria Azarenka of Belarus pounded China's Zheng Jie 6-1, 6-1; 11th- seeded Pole Agnieszka Radwanska held off Slovakian Daniela Hantuchova 6-3, 3-6, 6-3; 14th-seeded Marion Bartoli of France posted a 6-4, 6-2 win against compatriot Aravane Rezai; and Li Na, the 15th seed from China, notched a 7-5, 6-0 victory over Russian Vera Dushevina.

In other second-round action, Russian Elena Vesnina defeated Roberta Vinci of Italy 6-1, 7-6 (8-6), Iveta Benesova of the Czech Republic outlasted Argentine Gisela Dulko 6-3, 3-6, 6-4, and Czech Lucie Safarova trumped China's Peng Shuai 6-3, 4-6, 6-4.

In third-round action here on Wednesday, Jankovic will take on Vesnina, Azarenka will battle Safarova, and Sharapova will encounter her countrywoman Kleybanova.

This week's winner will take home $350,000.