Nadal holds a 15-3 edge over Wawrinka in head-to-head meetings -- including 5-1 on clay -- and is looking for make it 10-for-10 in French Open finals.
"Nine actually is my favorite number," Nadal said afterward. "But again, don't get me wrong. I would prefer 10 over nine, no doubt."
The Spaniard's French Open performance is one of the best ever in a Grand Slam final.
He hasn't dropped a set in any of his matches and has lost just 29 games. Only legendary Bjorn Borg (1978) had fewer losses (27) entering into a final, which also occurred in the French Open.
Nadal dispatched Thiem in two hours, seven minutes and will be looking for his 15th Grand Slam title when he squares off against the powerful Wawrinka.
"It's true that I have been having a great tournament," Nadal said. "But Stan is playing unbelievable so it's going to be a very tough match. I saw him hitting the ball so hard so I am going to have to play my best match."
Wawrinka was on the court more than twice as long as Nadal by prevailing in a four-hour, 34-minute marathon.
Wawrinka's fitness proved the difference as the 32-year-old from Switzerland dominated a fatigued Murray in the final set at Paris.
"With this sort of atmosphere, this sort of crowd, it was amazing to play in this match," Wawrinka said courtside. "I know I dominated him even though I was down two sets to one. But Andy is always there, does strange things with drop shots, and makes it very difficult for you.
"It's incredible to be back to the finals here again. I'm just going to try my best. After this, I want to celebrate and then I want to recover for Sunday. I think I'll have another chance to win."
Wawrinka was beaten in the semifinals of his title defense last year by Murray, who would go on to lose to Djokovic in the final.
This time, Wawrinka managed to wear down the 30-year-old Scot, also a three-time Grand Slam champion.
Both players delivered their finest tennis in front of an enthralled crowd at Philippe Chatrier court.
Wawrinka used his one-handed backhand and hammering forehand to send Murray scrambling and sliding all over the red clay.
Wawrinka took 16 of the first 21 points in the fifth set and went up 5-0. He ended the day with a backhand down the line for his 87th winner -- 51 more than Murray's 36.
Wawrinka is the oldest man in a French Open title match since 1973.