Serena Williams beat Dutchwoman Kiki Bertens in two tough sets to reach the French Open final, where she will play fourth seeded Spaniard Garbine Muguruza with her 22nd grand slam singles title at stake.
Defending champion Williams, who won the first of her three Roland Garros crowns in 2002, started slowly for the second day running, her early play littered with the unforced errors that had characterised Thursday's laboured three-set quarter-final win against Kazakh Yulia Putintseva.
The champion was broken in the first game by her unseeded opponent who, entering the contest on a 12-match winning singles streak in all competitions, showed no sign of nerves in her first major semi-final.
Williams eventually took the first set 7-6 on a tiebreak that she edged 9-7, settling into a more comfortable rhythm in the second set, which she won 6-4.
"The first set was not very easy but I think that today I played better. (Bertens) played very well," Williams said courtside.
For 58th-ranked Bertens, Friday's defeat marked the end of an unprecedented major run she dubbed "crazy" after her quarter-final win on Thursday over Swiss eighth seed Timea Bacsinszky.
In the final Williams will attempt to equal Steffi Graf's professional-era record of 22 grand slam singles titles.
Meanwhile Garbine Muguruza controlled a late bout of nerves to reach her second grand slam final, beating Australian Samantha Stosur 6-2 6-4.
The Spanish fourth seed, runner-up at Wimbledon last year, became the first Spanish woman to reach the Roland Garros final since Conchita Martinez in 2000.
"I have learned a lot how to control my emotions inside the court and outside the court. I think it's very important, because sometimes it's not too good to show them or not controlling them," Muguruza told reporters.
"In a tournament like this you have to be very focused. It's very long. Even longer with this kind of weather that you have to wait a lot. Here I'm learning. Here just I'm putting everything into that and it's going well."