Mauresmo was due to play Daniela Hantuchova in the last eight

The 26-year-old Frenchwoman beat Samantha Stosur in straight sets on Wednesday to reach the quarter-finals.

But she aggravated a problem with her right shoulder which caused her to pull out of the Porsche Grand Prix event in Stuttgart two weeks ago.

Fourth seed Elena Dementieva made an early exit from the event after a heavy defeat by Katarina Srebotnik.

The Russian, seeded fourth, had not lost in six previous encounters with the Slovenian.

But Srebotnik ended that dismal run with a comprehensive 6-1 6-4 victory and goes on to face another Russian, Maria Kirilenko, in the last eight.

In the first set I wasn't really doing the right things and there were a lot of ups and downs Maria Sharapova

"I didn't have enough patience today," said Dementieva. "I just kept going for winners.

"I didn't take my chances when I could have, especially in the second set. I just couldn't break her."

Russian second seed Maria Sharapova reached the quarter-finals with a 6-4 7-6 (7-4) win over unseeded Israeli Shahar Peer.

Sharapova, who has said she does not support on-court coaching, called on coach Mike Joyce after the first set for some advice after struggling to overcome Peer.

"I didn't feel desperate but I did feel in the first set I wasn't really doing the right things and there were a lot of ups and downs," she said.

"He basically just reminded me of some things."

Sharapova's third-seeded compatriot Svetlana Kuznetsova was given a tough match by Serbia's Jelena Jankovic but eventually won 7-6 (8-6) 7-5.

Their match was repeatedly interrupted by disputed calls, with Jankovic calling for the tournament referee at one stage.

Italian eighth seed Francesca Schiavone was forced to retire with a right calf injury after losing the first set 6-1 to Switzerland's Timea Bacsinszky.