TORONTO, Canada - Seeds went one for four on Monday, with Agnieszka Radwanska moving safely through but Marion Bartoli, Amélie Mauresmo and Nadia Petrova all faltering.  Toronto: Monday Highlights

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Radwanska, debuting in Canada as the No.14 seed, got past Carla Suárez Navarro, 63 63, rallying from 1-3 in the first set and grinding out a 59-minute second set.  Highlights: A.Radwanska vs. Suárez Navarro

Elsewhere, No.13 seed Bartoli lost quietly to Alona Bondarenko, 64 63, and No.15 seed Mauresmo was outdone by Francesca Schiavone in a see-saw three-setter, 62 36 61.  Highlights: Schiavone vs. Mauresmo

Other winners during the day were Samantha Stosur, Patty Schnyder, Sybille Bammer, Agnes Szavay, Aravane Rezai, Ai Sugiyama and qualifiers Roberta Vinci and Kateryna Bondarenko. Bammer had the most dramatic win of them all, rallying from 63 41 down to beat Anna Chakvetadze, 36 64 62.

In the feature night match, No.10 seed Petrova fell to Maria Sharapova, 63 64, her seventh straight loss to her and the eighth in their nine career meetings.

"When you're out there, you forget who you're playing, whether it's your compatriot or someone from another country. It's all about the job ahead and your own side of the court," Sharapova said. "I was the tougher one in the end. She had chances to make the match 5-all in the second, and it was good I finished it in two. I just hang tough no matter the score - not just with her."

The remaining 12 first round matches will take the court Tuesday, as well as the first two second round matches, pitting No.3 seed Venus Williams against Kateryna Bondarenko and No.6 seed Svetlana Kuznetsova against Stosur.