After being thrashed 6-1 in the second set against Agnieszka Radwanska, two-time grand slam winner Svetlana Kuznetsova needed a break.

And when the 25-year-old Russian returned from the players' dressing room, she turned the match around for a 6-4, 1-6, 6-3 victory on Thursday that put her into the quarter-finals of the US$2 million Rogers Cup at Uniprix Stadium.

What did she do during the brief break?

"I take a vodka shot, no?" Kuznetsova said with a laugh. "No, nothing like that.

"I just go to the locker-room, change all my clothes, eat a banana, and I go back. It's very simple. It was 6-1, but almost every game was deuce, so it was pretty hard. I took a break and it worked."

The win put 11th-seeded Kuznetsova into a quarter-final on Friday against Zheng Jie of China, who upset fourth-seeded Elena Dementieva 7-6 (3), 6-4.

Fifth-seeded Kim Clijsters advanced with a 6-2, 6-1 win over Kaia Kanepi of Estonia and will next face Vera Zvonareva, the eighth seed from Russia who downed Agnes Szavay of Hungary 6-3, 6-3.

In other day matches, Victoria Azarenka, the 10th seed from Belarus, downed ninth-seeded Li Na of China 6-3, 6-3 and 17th-seeded Marion Bartoli of France ousted Czech qualifier Iveta Benesova 6-0, 6-1. Benesova was coming off an upset win over top-seeded Jelena Jankovic.

Azarenka and Bartoli will face off in the quarter-finals.

It has been a difficult year for Kuznetsova, who was the first Russian woman to win the U.S. Open in 2004 and added a French Open title to her resume in 2009.

Back at Roland Garros as defending champion in May, Kuznetsova was beaten in the third round and the massive loss of points dropped her ranking out of the top 10 to 19th in the world. Then she went down in the second round at Wimbledon, among other dubious results in 2010.

But when she crossed to North America for the hardcourt season, things seemed to turn around. It was capped by a tournament win in San Diego two weeks ago, when she beat Radwanska in the final.

"I'm not used to having (played) so few matches," said Kuznetsova. "It's hard because the other players had so many matches from the start of the season.

"It's almost the end and I'm just warming up. Now I'm just starting to get into shape, but anyway, better late than never."

Her promising form may also bode well for the U.S. Open, which begins Aug. 31 in New York. As well as her victory, she also was reached the final in 2007, losing to her nemesis Justine Henin, who isn't at the Rogers Cup. In her career, Kuznetsova is 2-16 against Henin.

"I love to play in the U.S. Open," she said. "It's good when you get there and you know that at least you have a game and you know what you're doing on the court. I'm looking forward to it."

Clijsters was glad to have played well in an afternoon match after having to stay up late to win a difficult second-round match over American Bethanie Mattek-Sands on Wednesday night.

"It was nice to have an easier match than (Wednesday) and to get back to the hotel earlier," said Clijsters, who is 5-1 in her career against Zvonareva.

However, the Belgian former world No. 1's only loss to Zvonareva was the last time they played -- in the Wimbledon quarter-finals this year.

"I think we always had tough matches, a lot of three-setters or very tough ones," said Zvonareva. "I never managed to beat her and finally at Wimbledon, I was able to play very consistently and managed to beat her.

"I always believe I could beat anyone on the other side of the net. You have to come out there and not only know the game plan, but be able to execute it. It is very important to play your best to beat someone in the quarter-finals in such a big event."