Jelena Jankovic required three sets to see off the challenge of Danish teenager Caroline Wozniacki in the fourth round of the US Open.
A shock looked on the cards when the Serbian second seed surrended the first set 3-6 to her 18-year-old opponent.
But Jankovic came to terms with the windy conditions on Arthur Ashe and stormed through the second set 6-2.
And it was one-way traffic in the decider as the world number two's superior fitness told, allowing her to comfortably close out the match 6-1.
"I had to really play a lot more aggressive because it's quite windy and she was a lot more solid than I was in the first set," said Jankovic, who is chasing a maiden grand slam title at Flushing Meadows.
"I took a bit more control in the second and cruised through in the third so I am really pleased."
The 23-year-old is one of four players who can overtake compatriot Ana Ivanovic as world number one at the end of the tournament.
"It (the number one ranking) is a goal, but I want to win a grand slam," added Jankovic.
"Of course, by winning a grand slam I will regain the number one ranking again, and that is something I want really bad. I will try my best to achieve that."
Jankovic will face 29th seed Sybille Bammer in the quarter-finals after the Austrian won an epic encounter 7-6 (7-3) 0-6 6-4 with 12th seed Marion Bartoli.
Bartoli struggled early on in the humid conditions and had to call the trainer to have her blood pressure checked during the first set.
The Frenchwoman recovered sufficiently to dominate the second set, but Bammer regrouped in the decider to seal victory in three hours and three minutes, the equal longest women's match in US Open history.