The Spanish world number one took his Roland Garros win-loss record to 86-2 as he captured his 17th Grand Slam title by demolishing the seventh seed, who was hoping to become the second Austrian to win at Roland Garros.
In 11 finals in Paris, Nadal has only lost six sets as he matched the all-time record of most singles titles won at the same Grand Slam event set by Margaret Court at the Australian Open during the 1960s and 70s.
Monday morning's (AEST) result marks the sixth consecutive Grand Slam won by either Nadal or 20-times major champion Roger Federer.
The muscular Spaniard had won all 10 of his previous Roland Garros finals and although Thiem was the only man to have beaten him on clay over the past two seasons, the Austrian never threatened the claycourt master on Sunday.
Nadal called on the trainer to get his forearms massaged twice in the final set but even that problem failed to improve Thiem's chances of emulating fellow Austrian Thomas Muster's 1995 triumph.
Nadal got off to a dream start, pocketing the first six points of the match as he broke Thiem in the second game to open up a 2-0 lead.
Thiem broke back immediately as he continued to go for his shots, and he saw off a break point to hold for 2-2.
