Fourth seed Venus Williams retired from her Australian Open third round match against Germany's Andrea Petkovic with injury on Friday after lasting just seven points.
The seven-times Grand Slam champion pulled up with what appeared to be a groin strain after lunging for a return with the German leading by a game and 30-0 in Melbourne.
- Images from the Australian Open
Petkovic moves on to face former champion Maria Sharapova in the fourth round.
Williams strained a muscle in the same area during her second round victory over Czech Sandra Zahlavova on Wednesday.
Her retirement leaves a Grand Slam without an American woman in the last 16 for only the fourth time, the last time coming at the French Open in 2008.