Serena storms into semis

Toronto - World No 1 Serena Williams, who is seeking her eighth title of the year, stormed into the semi-finals at the WTA Rogers Cup with a crushing straight-set win over Magdalena Rybarikova.

The 31-year-old Williams blitzed the world number 42 Slovak 6-1, 6-1 in a quarter-final match that took just one hour on Friday.

"She had nothing to lose," Williams said of Rybarikova. "I knew I had to play really, really good today."

Williams next faces third-seeded Agnieszka Radwanska of Poland on Saturday for a spot in the final.

Radwanska powered her way past Sara Errani of Italy 7-6 (7/1), 7-5 in an earlier quarter-final match.

It was a powerful display of tennis from the top seed Williams, who hammered seven aces and broke Rybarikova a half dozen times.

"I'm definitely happier with the return game today," Williams said. "I could still use some improvement. She served pretty well, but I was pretty happy with the results from today."

Williams is 8-0 since her fourth-round loss at Wimbledon to Sabine Lisicki.

"I just felt like I was too tight, and just put a lot of pressure on myself there," she said of the loss at Wimbledon. "I just needed to relax more than anything, which is what I'm doing."

Unseeded Romanian Sorana Cirstea also sent defending champion Petra Kvitova packing on Friday in the quarter-finals.

"It might come as a surprise for many people," said Cirstea of her upset win. "It's not really a surprise for me, because I know how hard I have been working for the past couple of weeks. "It's nice to see the reward."

Cirstea rallied for a 4-6, 7-5, 6-2 victory over sixth-seeded Kvitova and advanced to a semi-final clash with China's Li Na, the woman Kvitova beat in the final last year when the tournament was held in Montreal.

Li battled through a tight first set then coasted to a 7-6 (7/1), 6-2 victory over Dominika Cibulkova to reach the final four.

The fourth seed from China, playing her first tournament since a quarter-final appearance at Wimbledon, needed an hour and 36 minutes to get past unseeded Slovakian Cibulkova, who launched her hardcourt build-up to the US Open with the Stanford title a fortnight ago.

Li admitted she was a bit weary after a tough, three-set win over former world number one Ana Ivanovic on Thursday. She didn't feel like she was hitting a lot of winners, and was pleased to see in the match statistics that she fired 33 winners.

Getting through the first-set tiebreaker gave her a boost.

"After the first I was thinking 'OK, one set in the pocket' so I was feeling more confident, of course," she said.

In a match that featured a total of 15 service breaks, Poland's Radwanska managed to hold in the final game of the contest to secure the victory and avenge a quarter-final loss to the Italian at Roland Garros this year.

After an early exchange of breaks in the third set, Radwanska broke Errani for a 5-4 lead, but dropped her serve in the next game.

She broke Errani again for a 6-5 lead and a chance to serve for the match, and this time made no mistake, taking a 40-15 lead and securing the win after two hours and one minute with a thumping forehand that Errani couldn't get back.

Williams has beaten Radwanska in all five of their previous contests.

"It's a good match-up," Williams said. "She does everything so well. She's having a much better year. It's going to be an interesting match. It's definitely not going to be easy. I hope I can play well.

"I can only hope that I come out on top."