Dominic Thiem will have to down the King of Clay to secure French Open glory, but coach Nicolas Massu insists his man has a chance.

The Austrian closed out an epic victory over Novak Djokovic on Saturday, his 6-2 3-6 7-5 5-7 7-5 triumph unfolding over the space of two days amid rain and high winds in Paris.

Having denied the world number one the opportunity to hold all four grand slams at once, Thiem now faces the even greater challenge of taking on 11-time Roland Garros champion Rafael Nadal on Sunday.

Massu acknowledged the magnitude of the task but talked up Thiem's hopes of avenging last year's straight-sets loss to the Spaniard. 

"Rafa won 11 times here. I think he's the best player in history on clay," said Massu. 

"I don't know if there's going to be another guy like him. We respect Rafa a lot because, besides his unbelievable talent, he's a great player, a great person.

"It's an unbelievable match for the people, the crowd, for the French Open. The final is between guys that have unbelievable results on clay.

"Dominic understands that if he wants to win, he has to be very focused from the first ball to the last one.

"This was one of the biggest wins of his career, a semi-final against [the] number one in the world, and now he will play the best player in history on clay.

"So, when you arrive to this stage of your career in a tournament, it's because you are doing things well.

"I think that he is going to try to do his best, and I think he has a chance.

"But he plays against the number one in the world of clay in the history, it's true. We will try to do our best."