Toronto - World No 1 Serena Williams easily booked her spot in the quarter-finals of the WTA Rogers Cup, routing 13th-seeded Kirsten Flipkens in straight sets on Thursday.
Two-time champ Williams avenged a first-round loss by her sister, Venus, to Flipkens, beating the Belgian 6-0, 6-3 in a third round match in the $2.4 million tournament at the Rexall Centre stadium.
"After I won the first set I definitely thought about Venus, and I thought about what a good comeback Kirsten had, so I thought, 'I'm not going to get over-confident,'" Williams said. "I was just trying to stay really focused as well as really intense at that moment."
Flipkens, a surprise semi-finalist at Wimbledon, ousted Venus Williams 0-6, 6-4, 6-2 in the first round.
But she couldn't repeat the upset against Serena, the reigning US Open and French Open champ. Serena won this tournament in 2001 and 2011 and was the runner-up in 2000.
Williams blasted 10 aces, had one double fault and lost just one point (14 of 15) on her second serve in the 56-minute match.
Williams moves on to the quarter-finals where she next faces Slovak Magdalena Rybarikova.
Williams meanwhile said she is pleased to have Venus back on tour after her older sister missed substantial time with injuries.
"I'm happy she's around," Serena said. "She's trying to get in the swing of things and play some matches and get more match tough, but it's always good to have her around, and it's good for her to be back."
Williams wasn't the only top player to win in straight sets to get into the quarter-finals Thursday as third seed Agnieszka Radwanska and Czech left-hander Petra Kvitova also advanced.
Chinese star Li Na had a tougher time against former world number one Ana Ivanovic, rallying to beat the stubborn Serb 3-6, 6-1, 7-6 (7/5).
"Sometimes you can't play your best, but you just hang in there until the end," said Li, who lost to Kvitova in last year's Rogers Cup final.
French seventh-seed Marion Bartoli was upset by Rybarikova 7-6 (7/5), 1-0. Bartoli retired with abdominal pain after losing the first game of the second set.
Bartoli said after the match that her abdominal trouble could be a carry over from her gruelling Wimbledon triumph.
Last week Rybarikova captured her second consecutive Washington, D.C. crown.
The 31-year-old Williams will be facing the younger Rybarikova, 24, for the first time in their careers.
Kvitova earned a spot in the round of eight by rolling over Aussie Samantha Stosur 6-3, 6-3.
Meanwhile, Radwanska dispatched 14th-seeded American Sloane Stephens 6-1, 7-6 (7/2) and fifth-seeded Italian Sara Errani outlasted France's Alize Cornet 7-5, 7-6 (7/3).
Radwanska, the 2012 Wimbledon runner-up, and Errani will face each other in the quarters with Radwanska leading 6-2 in their head-to-head career series. Errani won their last encounter earlier this year.
"We always play long matches," Radwanska said. "We play a little bit similar. That's why there's a lot of running and a lot of long rallies with us."
Romanian Sorana Cirstea surprised 15th-seeded Serb Jelena Jankovic 6-3, 6-4 and Slovak Dominika Cibulkova stunned Roberta Vinci of Italy 6-3, 7-6 (7/4).
Results on Thursday from WTA event in Toronto (x denotes seed):
Magdalena Rybarikova (SVK) bt Marion Bartoli (FRA x7) 7-6 (7/5), 1-0 - retired
Agnieszka Radwanska (POL x3) bt Sloane Stephens (USA x14) 6-1, 7-6 (7/2)
Sara Errani (ITA x5) bt Alize Cornet (FRA) 7-5, 7-6 (7/3)
Li Na (CHN x4) bt Ana Ivanovic (SRB x16) 3-6, 6-1, 7-6 (7/5)
Dominika Cibulkova (SVK) bt Roberta Vinci (ITA x10) 6-3, 7-6 (7/4)
Sorana Cirstea (ROU) bt Jelena Jankovic (SRB x15) 6-3, 6-4
Petra Kvitova (CZE x6) bt Samantha Stosur (AUS x12) 6-3, 6-3