In the other semi-final, Marco Cecchinato's unusual run in the last two weeks was ended by Dominic Thiem, also in straight sets, although the first two sets were somewhat closer than anything Del Potro could muster.
"For me, the motivation to play here always is high, high as possible", said Nadal after breezing past Juan Martin del Potro 6-4, 6-1, 6-2 in Friday's semi-finals in what was his 85th win in Paris against just two defeats.
Nadal has now won 17 Grand Slam titles - three lesser than great rival Roger Federer - and matched the all-time record of most titles won at the same Grand Slam event set by Margaret Court at the Australian Open during the 1960s and 70s.
Can you see Thiem denying Nadal a record-extending 11th title at Roland Garros?
Thiem's fighting spirit was evident in abundance - he continued to put pressure on Nadal through his return game, while consistently scrapping to stave off perilous positions on his own serve - but ultimately the Spaniard's quality and, often, his sheer force of will, won the day.
"That's my biggest goal, to get into the next one and then to do it better than today", he said.
The King of Clay.
Whatever the issue was, Thiem could not earn the break back-giving up another one while serving down 4-2-and Nadal took the third set and the title.
Sunday marked the first time Nadal had faced a player from a younger tennis generation in a Grand Slam final.
Despite his remarkable efforts, the 32-year-old remains three titles behind Federer, who will be targeting a 21st Slam win at Wimbledon next month.
There was a nervy moment when Nadal called his trainer to the court on several occasions as he appeared to be suffering from cramp in the fingers of his racket hand.
'Of course I would love to have 20 like Roger in the future or even more, but being honest, is something that is not in my mind. After guzzling water during that break, Nadal felt better and was back to playing his unmistakable brand of almost unbeatable clay-court tennis. Like so numerous pretenders, Thiem just did not have quite the same level of consistency to derail the Spaniard, who ruthlessly targeted his flowing backhand.
Ruthless Nadal proved far too good for Kevin Anderson as he claimed a 16th Grand Slam title at the US Open.
That was swatted away with Nadal's double-handed backhand, though, and the second set duly went the way of the favourite.
German six-time Grand Slam victor Boris Becker: The legend continues. Thiem did force Nadal to save a breakpoint, but a less aggressive approach due to the mounting enforced errors meant there was little pressure on Nadal.
The number of Masters 1000 titles won by Nadal, the most by a single player since the series began in 1990.