NEW YORK, NY, USA - Two former world No.1s will clash for a spot in the quarterfinals of the Open, after Kim Clijsters and Ana Ivanovic both won their third round matches in straight sets in Flushing Meadows on Friday.

Clijsters, a two-time US Open champion and the No.2 seed here, was the first of the pair to advance, losing the first three games then snapping into top form, reeling off 12 straight games to take down No.27 seed Petra Kvitova, 63 60.

"Even though I was 3-0 down I felt I had opportunities," Clijsters said. "That's tennis. until the set is over, you can always come back and win. As long as I could counterpunch her tough shots and go to the open court, take those extra steps, I felt I was getting her out of her comfort zone. That's what I focused on."

The Clijsters winning streak at the Open is now at 17 matches, seven coming in her 2005 title run, seven more coming in her 2009 title run and now three this year. Ivanovic will try to stop her, after her 75 60 win over Virginie Razzano.

Clijsters leads Ivanovic in their head-to-head, 2-0, although the last win for Clijsters came via a foot injury retirement just a few weeks ago.

"Ana and I are good friends. I'm happy to see her doing well again," Clijsters said. "I followed her very closely when I wasn't playing. I saw her win the French Open and lose it a little bit from there. She had some injuries when I played her in the Cincinnati semifinals as well - the three games we played there were pretty good tennis, so I hope we can have kind of a rematch here."

"It's going to be a tough match, no doubt about it. But I'm really looking forward to it, because I was really disappointed I had to stop in Cincinnati," Ivanovic said. "It's a new opportunity for me. Kim is a great player. She hasn't lost a match here in a long time. In some ways we have similar games. I think it's going to be a fun match. It's going to be exciting, no matter what."