Romanian Simona Halep reached the US Open fourth round on Saturday with a 6-1, 2-6, 6-4 over Hungarian Timea Babos.

"I don't know how I came back," said Halep, whose unforced errors skyrocketed in the second set. "I was fighting to the very end for every ball."

Having regained the break to level the third at 3-3, Halep was unable to convert two break points in the eighth game.

But Babos, unable to convert two game points in the 10th, finally surrendered with a whimper with a double fault on match point.

Halep, who fell in the semi-finals to eventual champion Flavia Pennetta last year, will play Spain's Carla Suarez Navarro for place in the quarter-finals.

Suarez celebrated her 28th birthday with a 6-4, 6-3 victory over Russian Elena Vesnina.