Wozniacki, Stosur knocked out in Miami

MIAMI, March 28 (UPI) -- Top-seeded Caroline Wozniacki of Denmark and fourth-seeded Samantha Stosur of Australia were upset Monday at the Sony Ericsson Open in Miami.

Wozniacki was ousted in the fourth round by Andrea Petkovic of Germany, 7-5, 3-6, 6-3. Maria Sharapova, seeded No. 16, took care of Stosur in surprisingly easy fashion, 6-4, 6-1.

While Wozniacki is the dominant women's player, Petkovic is off to a strong start this season, finishing second in a tuneup for the Australian Open and then making the quarterfinals of that Grand Slam event.

Petkovic will next play the winner of the fourth-round match between Jelena Jankovic and Anabel Medina Garrigues.

Sharapova, coming off a loss to Wozniacki in the semifinals at Indian Wells last week, will next take on Romania's Alexandra Dulgheru, who advanced to the quarterfinals with a 6-3, 6-4 win over China's Peng Shuai.

Second-seeded Kim Clijsters was to face former world No. 1 Ana Ivanovic in another fourth-round match Monday night.