The op seed Ana Ivanovic of Serbia withdrew from the Olympic tennis event with an injury to her right thumb.
The 20-year-old Serb says it's one of the hardest moments of her career and one of the hardest decisions she's had to take.
Ivanovic will be replaced by fellow Serb Jelena Jankovic at the top of the world rankings today says she hasn't been able to practise since arriving in China.
She's heading home in a day or two to try to recover in time for the U.S. Open.
Ivanovic joins a growing list of injured players who have pulled out..
Maria Sharapova withdrew with a shoulder injury, Lindsay Davenport pulled out of the singles on Friday with a knee injury and Croatians Ivo Karlovic and Ivan Ljubicic both withdrew from the singles on Saturday.
