The No.1-seeded Williams had never lost to Petkovic in their four previous meetings and this one went much the same way, as she held all nine of her service games – never even facing a break point – and broke the No.16-seeded Petkovic three times en route to a 6-3, 6-2 victory in just 62 minutes.
She will next face Roberta Vinci after the Italian eased past Russia’s Daria Gavrilova 6-4 6-3. “I served better and I’m happy that I could play my best in the important moments”.
“Personally, I think it was really bad for our sport, and hopefully he can learn and just, you know, really understand what’s going on around him”.
In the late match, fifth-seeded Ana Ivanovic of Serbia played Slovenia’s Polona Hercog.
The 16th-seeded Isner beat Kyrgios, 7-5, 6-3, in a third-round match marred by Kyrgios’ shouting match with a fan.
Serena Williams made serene progress into the quarter-finals of the Rogers Cup after a straight sets victory over Germany’s Andrea Petkovic.
The first set began in nip-and-tuck fashion as all nine games went with serve, but Williams, who led 5-4, pulled out a timely break to draw first blood. “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 added.
But Halep, runner-up at the French Open last year, did just enough to eliminate the 13th seed and advance to the quarter-finals against Agnieszka Radwanska, who beat France’s Alize Cornet 6-2 4-6 6-2.
“I knew I had to win it, because at the end I was so exhausted I couldn’t move anymore”. Fichman, from Toronto, and Zhao, of Richmond Hill, Ont., were a wild-card entry.
She was scheduled to team with Slovakia’s Dominika Cibulkova on Thursday night against Errani and Italy’s Flavia Pennetta.
Top-seeded Martina Hingis of Switzerland and Sania Mirza of India advanced with a 6-4, 6-2 victory over Hao-Chang Chan and Yung-Jan Chan of Taiwan.