Wozniacki starts slowly, wins in Germany

STUTTGART, Germany, April 21 (UPI) -- World No. 1 Caroline Wozniacki overcame a slow start Thursday before claiming a semifinal berth at the Porsche Tennis Grand Prix in Germany.

Wozniacki was down 1-4 in the first set but won 10 consecutive games and finished off a 6-4, 6-1 victory over Andrea Petkovic. Wozniacki dropped serve twice in falling behind but quickly turned things around. She won 65 percent of the points of the second set.

Agnieszka Radwanska was a 7-5, 6-3 winner over Kristina Barrois, the prize for which is the semifinal slot opposite Wozniacki, Radwanska is 1-3 versus Wozniacki, winning their first meeting in 2007.

The other semifinal pits fifth-seeded Samantha Stosur against Julia Goerges, who will be playing in her first premier-level semifinal. Goerges won her only previous match against Stosur.

Stosur improved to 6-2 lifetime against Vera Zvonareva, ranked third in the world, with a 2-6, 6-3, 7-6 (7-3) win Thursday that took more than 2 1/2 hours. Both players won 113 points in the match and both took 39 points in the third set.

Goerges, who lost her serve just once Thursday, was a 6-4, 6-4 winner over Sabine Lisicki in her quarterfinal.