Former world number one Caroline Wozniacki, one point from falling behind 5-0 in the opening set, rallied to upset ninth-seeded Russian Svetlana Kuznetsova in straight sets at the U.S. Open on Wednesday. The unseeded Dane, slowed by injuries this season, took advantage of some sloppy play by the former U.S. Open champion to post a 6-4 6-4 victory and advance to the third round. "It was not looking good for me," Wozniacki said on the Arthur Ashe Stadium court after the match. "I've been in this situation before. I was down 6-1 (actually 6-2), 4-1 (in the fourth round in 2009) to her once on this court I said 'I can do this, I can pull this through.' And I won last time and I won today and I'm really proud of that." Former world number one Caroline Wozniacki, one point from falling behind 5-0 in the opening set, rallied to upset ninth-seeded Russian Svetlana Kuznetsova in straight sets at the U.S. Open on Wednesday. The unseeded Dane, slowed by injuries this season, took advantage of some sloppy play by the former U.S. Open champion to post a 6-4 6-4 victory and advance to the third round. "It was not looking good for me," Wozniacki said on the Arthur Ashe Stadium court after the match. "I've been in this situation before. I was down 6-1 (actually 6-2), 4-1 (in the fourth round in 2009) to her once on this court I said 'I can do this, I can pull this through.' And I won last time and I won today and I'm really proud of that."