Serena to face Venus in all-Williams Doha final

Serena Williams has advanced to face big sister Venus in the final of the Sony Ericsson Championships after Caroline Wozniacki retired with an apparent abdominal injury when trailing 6-4, 0-1.

Wozniacki received medical treatment on her stomach muscles in the first set and decided to quit after breaking Williams to start the second. The 19-year-old Dane has been struggling with injuries all week, and said Friday that her aching abdominal muscles were affecting her serve.

Earlier, Venus Williams advanced to her second straight Sony Ericsson Championships final after rallying to beat Jelena Jankovic 5-7, 6-3, 6-4.