Former Australian Open champion Caroline Wozniacki rallied back to beat American Danielle Collins 4-6 6-3 6-4 on Thursday to secure a spot in the third round of the U.S. The Danish 19th seed, who has not been past the second round in New York since her run to the semi-finals in 2016, secured the victory when she served out to love in the final game. Collins, who reached the Australian Open semi-finals this year, did well to grab the first set but lost her way in the second when Wozniacki made the necessary adjustments and raced out to a 5-0 lead. "She started off very aggressively and I couldn't really find any rhythm," Wozniacki said in her on-court interview. "I just stayed determined and tried to take the ball earlier in the second and third sets … so she didn't have any opportunity to attack." Up next for two-times U.S. Open finalist Wozniacki will be in-form Canadian Bianca Andreescu, who beat Belgian qualifier Kirsten Flipkens earlier on Thursday to advance.