Stanford, CA -- (Sports Network) - Third-seeded Vera Zvonareva was upset by Australian Samantha Stosur Thursday in the second round at the $600,000 Bank of the West Classic tennis event.

Stosur dispatched her Russian foe 6-3, 6-2 to secure a spot in the quarterfinals.

Fifth-seeded Patty Schnyder of Switzerland and sixth-seeded Frenchwoman Marion Bartoli also were victorious on the hardcourts at Taube Family Tennis Stadium.

Schnyder beat Russian Alisa Kleybanova 7-6 (10-8), 6-4, and Bartoli outlasted British qualifier Anne Keothavong 6-3, 1-6, 7-5.

One other second-rounder saw Canadian qualifier Aleksandra Wozniak dismiss Austrian Sybille Bammer 6-4, 7-5.

The 2008 Stanford titlist will collect $95,500.