The world number one was taking part in the event for the first time in 14 years after repeatedly boycotting it in the past as a result of sister Venus Williams suffering racial abuse when she last competed here back in 2001.
Victory over Timea Bacsinszky set up a final-four spot for Williams, but despite receiving a pain-killing injection she was unable to take part in this morning's semi-final clash as a result of an injury to her knee.
"I was on the practice court yesterday and everything was going well, but literally the last two minutes I went for a serve and felt a super sharp pain in my knee," the American told reporters.
"I even did an injection. I've never done an injection before. If this were any other event I probably wouldn't have considered it. But I wanted to give 200%. It just wasn't meant to be this year."