Williams sweeps into last eight at Rogers cup

Serena Williams' preparations for the defence of her US Open title continued on Thursday night with a confident victory in Toronto. The 33-year-old is trying to become the first woman in 27 years to win all four grand slam crowns in the same year.

Serena Williams will try to win her 22 grand slam singles title at the US Open. Reuters

The world number one progressed with a straight sets win over the German Andrea Petkovic.

It was the American top seed's fifth consecutive success over Petkovic and the manner of her victory was in stark contrast to her stuttering start to the tournament against Flavia Pennetta.

In that match against the Italian veteran, her service was shaky as she dropped the first set.

But against the 16th seed, she struck nine aces and hit 28 winners to ease through 6-3, 6-2 in 62 minutes.

Williams never faced a break point and held all nine of her service games.

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

She will next face the Italian Roberta Vinci who beat the Australian 21-year-old Daria Gavrilova.

Second seed Simona Halep needed three sets to dispatch the German Angelique Kerber. The Romanian will next take on the defending champion Agnieszka Radwanska. The Pole came from a break down in the final set to dismiss the French woman Alizé Cornet 6-2, 4-6, 6-4.