World number two Maria Sharapova reached the quarter-finals of the WTA event in Stuttgart's while former world number one Ana Ivanovic suffered a shock first-round exit.
Sharapova progressed to the last eight of the clay-court tournament after French qualifier Alize Cornet was forced to retire after the first game of the second set with a shoulder injury in the second-round tie.
"You never want a match to finish like that, but we are approaching Roland Garros and, being French, she would want to be fit to be able to play in her home country," said Sharapova.
"I wish her the very best for a fast recovery.
"It is quite a task to adjust to clay, you need matches to find your game.
"The ball bounces differently and you have to be prepared for the longer rallies.
"The only thing that helps is playing matches, that is priceless."
Sharapova will face either US Open winner Samantha Stosur or Stuttgart's defending champion Julia Goerges, who meet late on Thursday (AEDT).
Sixth-seed Caroline Wozniacki is into the second round after opponent Jelena Jankovic was also forced to retire in their opening match.
Wozniacki took the first set 6-3, but Jankovic was forced to retire after 56 minutes with a back problem and the Dane will face Germay's Angelique Kerber for a place in the quarter-finals.
Polish fourth-seed Agnieszka Radwanska is already in the quarter-finals following her 6-3, 6-4 second-round victory over Hungary's Greta Arn.
Earlier, wild-card Mona Barthel was delighted by her shock first-round win over her former idol Ivanovic in straight sets.
The 21-year-old German blasted down 11 aces to out-muscle the Serbian, ranked 15th in the world, for a 7-5, 7-6 (7-4) victory and will now face seventh-seed Marion Bartoli of France in the second round.
AFPTags: tennis, sport, germany First posted April 26, 2012 06:05:35