Wozniacki into Brussels semis

Brussels - Top seed Caroline Wozniacki swept into the semi-finals of the Brussels Open on Thursday when Yanina Wickmayer retired with an injured back after losing the first two games.

The Belgian needed a medical timeout after the second game to receive treatment on her lower back. Wickmayer came back, hit a few weak returns of serve and called it quits to the disappointment of a few hundred fans at Primerose club.

Wozniacki will now play either French Open champion Francesca Schiavone or Japan's Ayumi Morita in Friday's semi-final.

Third-ranked Vera Zvonareva beat Alexandra Dulgheru of Romania 6-0, 6-1 to set up the other semi-final match against Peng Shuai.

Zvonareva won the opening 10 games before conceding one to Dulgheru. The Russian is looking for her second title of the season.

Peng, who is ranked 31st, defeated Sofia Arvidsson of Sweden 6-2, 6-4.