However, here a year ago in the semi-finals, Nadal destroyed Thiem, losing just seven games in a rout, but it is worth mentioning that Thiem triumphed in their last meeting in Madrid last month, in the quarter-finals.
The victory also allowed the 32-year-old Spaniard to hold onto the No. 1 ranking.
He's the only player to beat Nadal on clay in the past two years - in Rome last year and in Madrid last month.
Nadal has won 17 Grand Slam singles titles, three short of Roger Federer, the tennis yin to his yang, who has won a record 20.
Can you see Thiem denying Nadal a record-extending 11th title at Roland Garros?
Over the best-of-five sets on clay, Nadal improved to 111-2 - it is a figure nearly as imposing as the nearby Eiffel Tower - his lone reverses coming against Robin Soderling in 2009 and Novak Djokovic in 2015 at the French Open.
"You can win a set, but not a match against Rafa", said Del Potro keen not to over-egg any hint of weakness in Nadal's game.
"I think it was the first time against him here in Roland Garros where it was a fight", said Thiem, who told Nadal he remembered being 11 years old and watching the Spaniard win his first title in 2005.More news: Nabil Fekir: Liverpool target staying at Lyon, say Ligue 1 club
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This historical analysis doesn't lend itself to fancying Thiem's chances of denying Nadal an 11th French Open title this afternoon, and neither did my model pricing either.
Nadal celebrated in relatively low key fashion, but then there is not much novelty value in this.
Two breaks later Nadal was in a familiar position, serving for the title, and when another Thiem forehand dropped long, his arms were raised in celebration, yet again. After Nadal won the first, there was an air of inevitability.
But from the moment Nadal broke serve in the 10th game to win the opening set Thiem's belief ebbed away. Even a cramp in his left hand early in the third set, which required a rub-down of his left forearm, did not stop him as he closed out for victory.
Such is his motivation to win his 17th Grand Slam on Sunday, that the task facing Austrian 24-year-old Thiem was described as "almost impossible" by Del Potro.
At least Thiem has in the past found the key to unravelling the Nadal clay court enigma. Nadal's had some challenges at Roland-Garros' championship stage over the years, but few athletes in any sport have ever been more acclimatized to a venue the way Nadal has owned the terra firma of Roland-Garros' grounds.
"It is nice that after the final that she lost previous year with so many chances, having breaks in the second and in the third, I think, she was able to win a Grand Slam". Now, six Slams later, Federer still keeps his lead at three.
Thiem was considered the stiffest test for Nadal at the French Open and understandably so. When he first halted play, Nadal removed that tape, which he said let his circulation improve.