Serena Williams
Serena Williams displayed plenty of anguish on her way to winning in three sets (Getty Images)

World number one Serena Williams recovered from the brink of retirement to stage a remarkable revival to continue her pursuit of a 20th grand slam singles title by defeating Timea Bacsinszky in three sets to reach the French Open final against Lucie Safarova.

The American was suffering from a fever throughout the contest and looked set to be heading out via forfeit after trailing by a set and a break on Bacsinszky's maiden major semi-final appearance.

But Williams turned the match around in typically emphatic fashion by winning the last 10 games on the bounce to prevail 4-6 6-3 6-0 and reach a 24th final in major competition and deny her Swiss opponent a shot at a first grand slam title.

"I didn't want to lose without a fight," she said. "I wanted to find to some energy from somewhere. I don't' know where I found it."

Though questions may be raised over the legitimacy of Williams's illness, which saw her requiring regular intakes of water and adopt a jaded stance at the back of the court amid the searing conditions at Roland Garros, the dramatic turnaround was anything but out of character.

Comebacks from a set down has defined Williams's route to the semi-final and it was to be no different against Bacsinszky as, after going a set and 3-2 down in the second, she won the next 10 games in a row to cruise into the final.

Safarova will be charged with attempting to halt Williams's grip on the summit of women's tennis in the final on 7 June after she overcame 2008 champion Ana Ivanovic in straight sets in the first semi-final.

Safarova had knocked out defending champion Maria Sharapova on her way to the last four and she blew away Ivanovic despite going a break down in the first set, prevailing 7-5 7-5 from her third match-point.

"It's slowly sinking in and it's just amazing. The happiness is unreal," she said after reaching her first grand slam final.

"In the second set, I think when I realised that I finally can be in the finals, I got a little bit tense there. The game at 5-4 I was really like overthinking and couldn't really concentrate to be there in the moment.

"My serve wasn't working, and, yes, it was a little bit fighting with everything on the court at that moment. But when I lost the serve I, like, shake it off and started to play aggressive again, and then I served it out."