By Simon Cambers

NEW YORK (Reuters) - Top seed Amelie Mauresmo edged out Serena Williams 6-4 0-6 6-2 in a thrilling battle at the U.S. Open to reach the quarter-finals on Monday.

Twice former champion Williams had looked set for victory after roaring back from the loss of the first set but Mauresmo rallied to clinch a dramatic win and set up a clash with Russian Dinara Safina.

"I'm very excited," Mauresmo said.

"I'm pretty happy with the third set but let's forget (about the second). I'm glad I was able to really focus back into the match from the beginning of the third set."

The 27-year-old Frenchwoman dominated the early stages and took the first set but Williams ripped through the second set to level the match.

After a cagey opening to the decider, Mauresmo broke in the sixth and eighth games, clinching victory with an angled backhand drop volley.

Mauresmo was delighted to get a win over Williams, having lost nine of her 10 previous meetings with the American.

"It feels pretty good," the Australian Open and Wimbledon champion said.

UNDER PRESSURE

"Obviously when you don't have such a good record against an opponent you want to try to get a little bit better on the stats.

"But I knew it was going to be a very different match in terms of who's in confidence and who's in control right now, even though I hadn't played a lot coming in."

Since winning the Australian Open at the start of the year, the Mauresmo who was considered something of a choker under pressure has gone.

In her place is a confident, relaxed Mauresmo, not afraid to produce her best under pressure.

The Frenchwoman kept her nerve to beat Justine Henin-Hardenne to win Wimbledon in July and the way she recovered from losing the second set 6-0 to Williams suggests she is able to find her game even under the most difficult of circumstances.

"Maybe in these kind of situations before I would have acted differently in that third set," she said.

"But I just tried to leave it behind me and focus back on the game. I am getting old now, so maybe I am maturing."