Romanian Simona Halep showed the full extent of her defensive skills to beat Karolina Pliskova in three sets and reach her second French Open final.
The third seed, who will become world number one if she beats Latvia's Jelena Ostapenko in the final, benefited from her opponent's unforced errors in the first set before Pliskova rediscovered her touch.
Overwhelmed by Pliskova's power in the second set, Halep regained the momentum in the decider, frustrating her second-seeded opponent with her ability to soak up punishment.
She ended the contest on her first match point with an unreturnable serve to reach her second Roland Garros final after losing the first one to Maria Sharapova in 2014.
Ostapenko, celebrated her 20th birthday with a three set victory over Swiss Timea Bacsinszky in their semi-final.
The world number 47 became the first unseeded player to reach the women's singles final at Roland Garros since Mima Jausovec lost to Chris Evert in 1983.
She is also the first Latvian player to reach a grand slam final.