The World No 7 Thiem outclassed top seed Nadal earlier in Madrid Open in May this year and in the Italian Open last year.
"Because if you stay behind the baseline against Dominic, he can take advantage of it", Toni Nadal said. Cecchinato, who upset Novak Djokovic in the quarterfinals after winning two pulsating tiebreaks, rallied and even held three set points prior to Thiem triumphing 12-10.
He led by two sets plus a break early in the third, when the middle finger on his racket-wielding left hand was cramping so badly he couldn't straighten it.
This time, Thiem instead faced Cecchinato, a 25-year-old from Sicily who never had won a Grand Slam match until this tournament and was the lowest-ranked men's semifinalist at the clay-court major in 19 years.
"In every game that I served, I had problems".
The injury-prone Argentine had a discussion with Dr. Bernard Montalvan during the changeover, with Nadal leading 3-2 in the first set.
Rafael Nadal improved to 11-0 in French Open semifinals as he seeks his 11th title at the clay-court Grand Slam tournament, saving all seven break points he faced and overwhelming 2009 U.S. Open champion Juan Martin del Potro 6-4, 6-1, 6-2.
"He's a big favourite against everybody", Thiem said.
The 32-year-old Spaniard is also vying for his 17th major trophy, which would move him within three of Roger Federer.
But once a competive first set went the way of the world number one, the plan became damage limitation and Nadal's "undecima" never looked in any doubt.
There was a sense of inevitability when Del Potro served at 4-5 and Nadal turned the screws to grab two set points at 15-40. On the first date, Thiem defeated Nadal 6-4, 6-3.
"I think that was my chance of the match", Del Potro said of the ninth game.
It rarely is for Nadal at a place he has lorded over the way no other man ever has at any Grand Slam tournament.
Nadal tightened his grip, going to 5-1 on another double break in the third set and sealed the match when Del Potro hit a backhand long.World 72 Cecchinato had knocked out three seeded players to reach the semi-finals, including 12-time major victor Novak Djokovic in the quarter-finals.But Thiem, 24, was too strong and now believes he has a particularly powerful weapon on his side for the final - breakfast.
"Tough moment", Nadal would say later.
Ten-times champion Nadal then pounced in the 10th game to take the opening set and fifth seed Del Potro's challenged evaporated in the Court Philippe Chatrier sunshine.
By then, Nadal was finding his spots.
"It was a really close tiebreak and I didn't want that especially after I missed an easy volley at 6/4".
And the underdog soon faded as Thiem kicked on, racing to two swift breaks in the third and rescuing two break points to serve out the match in style.
The injury-plagued former US Open champion Del Potro wept courtside after beating third seed Cilic to reach the last four for the second time, but first in nine years.
The No. 6-seeded pairing from the Czech Republic beat Eri Hozumi and Makoto Ninomiya of Japan 6-3, 6-3 on Sunday.
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