Nadal, of Spain -- who has won Monte Carlo eight years in a row and was seeded No. 3 this year -- advanced with a 6-3, 7-6 (7-3) victory over Jo-Wilfried Tsonga of France.
Top-seeded Djokovic, of Serbia, followed into the finals of the French Open tuneup by dispatching Italian Fabio Fognini 6-2, 6-1. Djokovic did not face a break situation in the match, which lasted 52 minutes.
Nadal had a tougher time with Tsonga, who saved three match points in the final set.
Nadal holds a 19-14 lifetime advantage against Djokovic and has won 46 consecutive matches on clay. The two have not met since Nadal beat Djokovic in the French Open final last year.