Rafael Nadal reached his 14th French Open final on Friday after Alexander Zverev was forced to quit their semi-final after suffering a horror right ankle injury.

Zverev had to leave the court in a wheelchair after turning his ankle trailing 7-6 (10/8), 6-6 after more than three hours of play.

After screaming in anguish, a tearful Zverev was helped from the court by medics.

Minutes later, the 25-year-old returned to the court on crutches and conceded the match.

"It's very tough and very sad for him. He was playing an unbelievable tournament and he's a very good colleague on the tour," said Nadal.

"I know how much he's fighting to win a Grand Slam. For the moment, he was very unlucky. I'm sure he'll win not one, but much more than one. I wish him all the best.

"It had been a super tough match. Over three hours and we didn't even finish the second set. It's one of the biggest challenges on the tour when he's playing like he did today."

He added: "For me, to be in the final of Roland Garros is a dream, without a doubt, but at the same time, for it to finish that way... I have been there in the small room with Sascha and to see him crying like that -- I wish him all the best."

Nadal, chasing a record-extending 22nd Grand Slam title, will play either Marin Cilic or Casper Ruud in Sunday's final.