Serena Williams Advances In Rogers Cup

Top-ranked Serena Williams advanced to the Rogers Cup quarterfinals Thursday night, beating 16th-seeded Andrea Petkovic of Germany 6-3, 6-2.

"I think I served better," Williams said. "It was a big difference. I still think I have a tremendous amount of improvement to do off the ground and everywhere else."

A 21-time Grand Slam singles champion, Williams won titles in Toronto in 2001, 2011 and 2013. She will face Italy's Roberta Vinci, a 6-4, 6-3 winner over Russia's Daria Gavrilova.

Second-seeded Simona Halep of Romania also advanced, outlasting 13th-seeded Angelique Kerber of Germany 6-3, 5-7, 6-4 in hot afternoon conditions.