World number one Amelie Mauresmo denied nerves had caused her embarrassing defeat in the fourth round of the French Open on Sunday.

The Frenchwoman was humbled 6-7, 6-1, 6-2 by Czech teenager Nicole Vaidisova, whom she thrashed 6-1, 6-1 in January en route to her Australian Open triumph.

"I didn't feel that I was getting nervous, and especially looking at the way I played in that first set," Mauresmo told a news conference.

"But it's true that my shots were not so powerful or long enough. I think I just played with less intensity, so that she was able to come in and play really better," the top seed added.

"Also I was expecting for her to make a little bit more errors. I played her in Australia. She made some errors here but she didn't today."

Mauresmo looked poised for a win when she claimed the first set after winning the tiebreak 7-5.

Instead, 16th seed Vaidisova gallantly took her chance and dropped only three games on her way to the quarter-finals, where she will meet American Venus Williams [Images].

"The first thing that comes to me is that I went down a little bit physically at the beginning of the second set, and then my shots were not so disturbing for her," said Mauresmo.

"Then she could step in the way she likes to play and really played better and better."

The Australian Open champion said a lack of preparation could have contributed to her defeat. She was forced to pull out of the Italian Open with a sore throat and arrived in Paris having played only six matches on clay.

Mauresmo, however, was not depressed, saying clay was probably not her best surface.

"It's easier to impose my rhythm on a faster court. I'm thinking in particular of Wimbledon, starting from the serve," she said.

"My serve is a lot more dangerous and I can use it a lot more as a starting point. I'm more efficient on faster courts. So technically, it's just easier for me."

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