Serena Williams is gunning for her third French Open and 20th Grand Slam victory
Serena Williams fought back to beat Timea Bacsinszky and reach the French Open final despite being close to tears at times.
The top seed took 10 games in a row to win 4-6 6-3 6-0 and set up a final against Lucie Safarova on Saturday.
Williams, 33, has been unwell throughout the tournament and struggled as temperatures soared in Paris.
The American world number one is trying to win her third French Open and 20th Grand Slam singles title.
"I'm not sure how I did it," Williams said on court afterwards. "I just thought I didn't want to lose without a fight."
Lucie Safarova ecstatic after making it into her first Grand Slam final
Lucie Safarova fought back to beat Serbia's Ana Ivanovic and become the first Czech woman to reach the French Open final in 34 years.
The 13th seed trailed 5-2 in the first set but reeled off five straight games on her way to a 7-5 7-5 win.
She goes on to face world number one Serena Williams in Saturday's final.
"It is a dream come true. I cannot believe it," said Safarova after converting a third match point.
"I started slowly but tried to keep up the level and play really aggressively because that was the only way to win."
Safarova made the Wimbledon semi-finals last year, but is through to her first Grand Slam final.
The 28-year-old will try to match the achievement of her compatriot, Hana Mandlikova, who won the title in 1981.