Williams told reporters at Roland-Garros that she was having issues with her pectoral muscles, saying it's hard to serve.
But, with Williams chasing a fourth French Open title after taking almost a year out to have her baby daughter Olympia, she withdrew yesterday less than a hour before the match was due to begin.
Goolagong Cawley was in the stands on Court Philippe-Chatrier with daughter Kelly eager to see how Williams' comeback was coming along before the 23-times major victor withdrew from her scheduled fourth-round showdown with Maria Sharapova on Monday night (AEST). I always try to think positive'.
The match between Williams and Sharapova had been highly anticipated.
"I'm beyond disappointed", Williams added. "I had such a wonderful performance in my first Grand Slam back", she added. I can only take solace in the fact that I'm going to get better.
"It's been a while, and I think a lot has happened in our lives for the both of us in very different ways". I'm going to stay here and see some of the doctors here, see as many specialists as I can. She said it is the first time she has had to withdraw from a major tournament because of an injury. It didn't really get a lot better'.
Williams tried various tapings and support systems to help the injury during the doubles loss on Sunday, but said that nothing helped enough to allow her to play on.
Sharapova, herself making a comeback after missing the last two French Opens following a doping ban, will face Garbine Muguruza in the quarter-finals. Sharapova has won 10 of her last 11 grand slam quarterfinal appearances.
"It's very hard because I love playing Maria", Williams said.
'I wish her a speedy recovery and hope she returns to the tour soon'. "I have made every sacrifice that I could. I won't know (how serious the injury is) until I get those results". I made a commitment to myself and my team that if I wasn't at least 60% I wouldn't play.