NEW YORK - 23-year-old qualifier Taylor Townsend shocked former world No 1 Simona Halep at Flushing Meadows here on Thursday, defeating the Romanian 2-6, 6-3, 7-6 (4) to move into the third round of the US Open.

Townsend was emotional as she addressed the Arthur Ashe Stadium crowd afterwards. "It's been a long road. A lot of haters. A lot of people who weren't sure. I've heard it for a really long time that I was never going to make it, that I wasn't going to be able to break through."

"This was a huge, monumental moment. It was a very defining moment for me to realize that I belong here," added Townsend.

"I never played with someone coming so often to the net," Halep said. "Didn't miss much. It's unbelievable."

Other surprising results included Andrea Petkovic's 6-4, 6-4 elimination of two-time Wimbledon champion Petra Kvitova and, among the men, unseeded American Denis Kudla's 7-5, 7-5, 0-6, 6-3 win over No. 27 Dusan Lajovic, and unseeded Briton Daniel Evans' 6-4, 6-3, 6-7 (4), 6-4 defeat of No 25 Lucas Pouille.

Three-time US Open champion Rafael Nadal rolled into the third round when his opponent, Thanasi Kokkinakis, withdrew with an injured right shoulder.