World number three Mauresmo was playing her first tournament following a two-month lay-off after an appendicitis operation and despite winning Thursday's first set, Mauresmo struggled when the match resumed, losing 2-6, 6-1, 6-2 to Julia Vakulenko, ranked 53rd in the world.

Vakulenko then proved to be a giantkiller by beating eighth seed Dinara Safina 6-3, 5-7, 6-3 only a few hours later and is the only non-seeded player in Saturday's semi-finals where she will play Serbian Ana Ivanovic.

"It can happen when you have not played for a while," said Mauresmo, who will play in Rome's WTA tournament next week.

"I feel fine, I just wasn't able to play the way I wanted to. It was frustrating.

"I wanted to keep playing the way I did last night (Thursday), but what can you do?

"We have no control over the weather. I just need to keep practising and playing as many matches as I can.

"I wanted as many games as possible this week, but I only managed one game in five days, because of the weather.

"I will definitely be going to Rome, I need the matches and as many hours as I can on the court.

"I was late on every shot and she deserved the win.

"Coming here, I didn't know what shape I was in, so at least I know now what needs to be done."

Mauresmo was the second big name to crash out at the third round stage after Martina Hingis went down to Swiss compatriot Patty Schnyder 6-4, 6-0 on Thursday and promptly withdrew from Rome with a back injury.

Defending champion Petrova was the second surprise exit on Friday when she was beaten by third-seed Svetlana Kuznetsova in the quarterfinals after a tight struggle in the first set.

Having lost the tie-break 7-5, Petrova never recovered and ear-marked Kutznetsova, who will face either Jelena Jankovic or world number one Justine Henin in the semifinal, as a possible tournament winner.