Serena Williams will face Victoria Azarenka in a repeat of their Wimbledon semi-final at the Olympics but the All England Club bade farewell to a favourite daughter as Kim Clijsters was beaten by Maria Sharapova.
The Belgian will retire for the second time after the US Open later this month and will do so without an Olympic medal after her first and last Games was brought to an end.
Sharapova made a fast start and, although Clijsters delighted the Centre Court crowd by breaking back in the second set, she could not force a decider and lost out 6-2 7-5.
"It was great," said Clijsters. "It's a nice experience every time you go out on Centre Court so I'm happy to say that my last match at Wimbledon was on Centre Court."
Russia is now guaranteed at least a silver medal in the women's singles because in the last four Sharapova will face countrywoman Maria Kirilenko.
The 14th seed earlier pulled off a very impressive 7-6 (7-3) 6-3 victory over sixth seed and former Wimbledon champion Petra Kvitova.
"It makes me really happy that one of us will represent our country in the finals, going for gold," said Sharapova. "We're so happy."
Serena Williams continued her romp through the draw with another thrashing, her victim this time eighth seed Caroline Wozniacki.
The fourth seed has lost only 13 games in four matches after the 6-0 6-3 victory, and she said: "No matter what happens I am in a medal round now so I'm excited.
"I wasn't in a rush, I know I can rally up to 100 balls if necessary and when playing Caroline you have to be ready to do that. She is so consistent, she was number one for a reason."
Williams is likely to have a tougher time Friday against Azarenka, whom she edged out in two tight sets on her way to a fifth Wimbledon title four weeks ago.
Azarenka has had a more rocky road to the last four than Williams and she was given another battle on Thursday by seventh seed and Wimbledon semi-finalist Angelique Kerber from Germany before coming through 6-4 7-5.
Williams is still on track for two gold medals after teaming up with sister Venus to trounce French Open champions Sara Errani and Roberta Vinci from Italy 6-1 6-1 in the quarter-finals of the women's doubles.
Remarkably, if they were to win the title for a third time, both sisters would have four Olympic golds, more than any other tennis player in history.