Serena Williams survives longest match of her career to reach third round of Madrid Open . In Monday 's other second-round clashes , Serena 's fourth-seeded older sister Venus beat Russia 's Vera Zvonareva 7-5 6-3 . World No . 1 and unseeded Russian Vera Dushevina 6 - 7 ( 6 - 7 ) 7 - 6 ( 7 - 5 ) 7 - 6 ( 7 - 5 ) American will next play either 16th seed Nadia Petrova or Anastasia Pavlyuchenkova . Eighth seed Samantha Stosur wins to set up clash with Maria Jose Martínez Sanchez .
Serena Williams survives longest match of her career to reach third round of Madrid Open . World No . 1 and unseeded Russian Vera Dushevina 6 - 7 ( 6 - 7 ) 7 - 6 ( 7 - 5 ) 7 - 6 ( 7 - 5 ) American will next play either 16th seed Nadia Petrova or Anastasia Pavlyuchenkova . Eighth seed Samantha Stosur wins to set up clash with Maria Jose Martínez Sanchez .