The number one seed brushed aside his Argentine opponent with minimal fuss, edging the first set 6-4 before completing the win 6-1 6-2 in the heat on Court Philippe Chatrier.
Having ruthlessly turned around his quarter-final clash with 11th seed Diego Schwartzman, the Spaniard failed to drop a single serve as he produced an unstoppable display with Del Potro having no answer to his staunch defences and ferocious winners.
Nadal and Del Potro dazzle with duel at the net
Nadal, who saved all seven break points faced and has now won 33 of 36 sets in semi-final matches at Roland Garros, will face Dominic Thiem in Sunday's final after the Austrian seventh seed reached his first Grand Slam final by beating Italian Marco Cecchinato 7-5 7-6 (12-10) 6-1 earlier on Friday.
Nadal, who is only the second man to reach 11 finals at one Grand Slam after Roger Federer achieved the same feat at Wimbledon, said: “The first set was very difficult, there were lots of opportunities for Del Potro and I was perhaps a little lucky to win it.
"Without working hard and going through tough moments and being focused on your passion it is impossible to be here after so many years after my first final in 2005.
"Thiem is an amazing player. He beat me in Madrid and he has incredible power. I have done a lot of things well in the clay court season, it is going to be tough final but I believe I can be ready."
Highlights: Rampant Rafa brushes Del Potro aside
The 16-time major winner saw Schwartzman take a set off him in Paris for the first time since 2015, but Nadal survived a triple break-point before an injure scare to Del Potro appeared to swing the momentum away from the world number six.
A superb backhand crosscourt pass helped Nadal to make the crucial break and with it wrap up the opening set in 54 minutes, but what followed was a procession as Del Potro struggled to contain his frustrations at missing crucial chances to establish a lead.
Nadal’s defence work, snaring his opponent into unforced errors, resulted in an early break in the second but Del Potro’s service game deteriorated as he lost seven games on the spin to leave himself in need of a regroup, but it was one-way traffic.
Nadal somehow finds the line with trademark forehand
Nadal’s backhand was doing most of the damage, with three winners having set up the double break on his way to a two-set lead, and Del Potro was broken to love in his first serve game of the third, with Nadal inflicting a devastating backhand winner up the flank after another majestic defence.
The 32-year-old consolidated the break with a trademark forehand as Del Potro looked a beaten man, and another crosscourt return-winner from the King of Clay opened up the double break of serve.
The 10-time champion served out the match to complete his victory in two hours and 14 minutes and set up his date with Thiem, the pretender to his throne.