The French Open finalist Sara Errani and former Wimbledon runner-up Marion Bartoli have booked a quarter-final clash at the WTA's New Haven Tennis Open.
Italy's Errani, the fourth seed, defeated Spain's Carla Suarez Navarro 6-4 6-3, while fifth-seeded Bartoli of France survived a scare to beat American Sloane Stephens 6-1 0-6 6-3.
Bartoli trailed 0-3 in the third but won the next six games to advance in the US Open tune-up event.
Top-seeded Agnieszka Radwanska was due to open her campaign later in the day with a second-round clash against qualifier Olga Govortsova of Belarus.
Meanwhile, first-round action concluded as China's Zheng Jie defeated Bulgarian Tsvetana Pironkova 7-5 6-2 to set up a second-round match with eighth-seeded Czech Lucie Safarova.