Nadal is now just the second man to reach 11 finals at the same Slam, equalling Roger Federer's mark at Wimbledon.
The former US Open champion almost retired from the sport two years ago.
It is the 11th time the 32-year-old Spaniard has reached the French Open last four, becoming only the third man in history to achieve the feat at a Grand Slam tournament, after Jimmy Connors at the US Open and Roger Federer at Wimbledon and the Australian Open.
Rafael Nadal's straight-set victory means he establishes a new Open era best for consecutive sets won on a single surface.
John Isner blasted down 13 aces and took just one hour and 23 minutes to floor Juan Martin del Potro and book his place in Sunday's final.
Juan Martin del Potro sent his devoted fans home happy Tuesday by powering into the ATP Miami Open quarter-finals with a 6-4, 6-2 triumph over Serbian Filip Krajinovic.
Juan Martin del Potro and Marin Cilic are the biggest names left in a field lacking star power.
Roger Federer needs to advance to the quarter-finals in Florida to hold on to his number one ranking, or face being supplanted by old rival Rafael Nadal in top spot.
Juan Martin del Potro survived three match points before claiming the championship in a third-set tie-breaker.
Juan Martin del Potro is looking for his 22nd career and second straight ATP title in a row after winning earlier this month in Acapulco.
Milos Raonic didn't play in Indian Wells last year because of a string of injuries and surgeries that decimated his season.
World No. 8 Del Potro extended his win streak over the Spaniard to five straight matches, winning 6-4, 7-6 (7/3) at the ATP Tour hardcourt tournament here Tuesday.
South Africa's Kevin Anderson moved one step closer to capturing his second consecutive title.
Del Potro, the 2009 US Open champion and Auckland winner, beat Ferrer 6-4, 6-4 to continue his strong form from the end of last season.
The former US Open champion can take the eighth and final qualification spot for London from Pablo Carreno Busta if he reaches the semi-finals at Bercy, and he will face either John Isner or sixth seed Grigor Dimitrov in the last eight.
Roger Federer's victory boosts his hopes of taking the world number one spot from Rafael Nadal.
Rafael Nadal is chasing a seventh title in a season and a hat-trick of triumphs on the trot, having been crowned US Open and China Open champion in recent weeks.
Rafael Nadal defeated Argentine 24th seed Juan Martin del Potro 4-6, 6-0, 6-3, 6-2 to book a date in Sunday's final against South African 28th seed Kevin Anderson.
