Stuttgart, Germany: Top-seeded Caroline Wozniacki was knocked out of the second round of the Porsche Grand Prix on Thursday, losing 6-4, 6-4 to Lucie Safarova of the Czech Republic.
Wozniacki showed signs of still being bothered by a right ankle injury, which forced her out of the semifinal at the Family Circle Cup in Charleston, S.C., on April 17.
"I didn`t feel like I could move 100 percent," said Wozniacki, a U.S. Open runner-up last year. "And when you can`t move, it`s difficult to win."
The second-ranked Wozniacki had a bye in the first round.
Samantha Stosur of Australia rallied to beat Alexandra Dulgheru of Romania 3-6, 6-0, 6-2 for a place in the quarterfinals, extending her winning streak on clay to eight matches.
Safarova, ranked No. 38, made her second quarterfinal of the year and said she noticed that Wozniacki was struggling with the injury.
"I tried to make her run and to push her around," the Czech said. "I always need time to get used to clay, but now I am playing better."
Safarova, whose first-round opponent Selima Sfar of Tunisia retired with an ankle injury, landed 83 percent of her first serves and had five aces.
"She was making me run and that`s why she won," Wozniacki said. "I hate to lose, but now it`s important to get fit."
Stosur struggled against Dulgheru in the first set, but quickly regained the momentum.
"She played a decent game, well enough," Stosur said. "I was frustrated, but I tried to stay calm."