The seven-times SW19 champion left the court in tears after suffering an injury early in the match after slipping twice. She had began the tie with her thigh heavily strapped.
The 39-year-old American did not play last month’s French Open to prepare for the grass-court season as she tries to equal Margaret Court’s all-time record of 24 grand slam titles.
However, she was in obvious pain and decided to call it a day with the score 3-3 in the first set.
“I’m so sad for Serena,” Sasnovich said. “She’s a great champion, This happens sometimes in tennis.”
There is no guarantee that Williams, who is in the twilight of her career, will return to Wimbledon again, with her next chance of equalling Court’s success coming at the US Open in September.