The win continues Nadal's undefeated run on championship weekend in Roland Garros-the Spaniard has never lost in Paris after reaching the semifinals.
"I think that was my chance of the match", Del Potro said of the ninth game.
That win, according to three-times former champion Mats Wilander, should be all Thiem is thinking about when he prepares for Sunday's clash.
The first set was a tight affair, with Thiem claiming the decisive break in the 11th game but the Italian retained his composure to send the second to a tie-break.
Top seed Nadal, 32, trailed 6-4 3-5 when play was halted on Wednesday.
Paris - Dominic Thiem ended Marco Cecchinato's French Open fairytale on Friday, reaching his first Grand Slam final with a 7-5, 7-6 (12/10), 6-1 victory.
He beat the Spaniard in the Madrid quarter-finals this year having won in the Rome last-eight in 2017.
"But I have a plan".
Nadal goes past Borg's record of six titles and ends Djokovic's bid to be the first man since Rod Laver in 1969 to hold all four majors. "But I got closer to them, just asking 'Who was it?' I'm still trying to find the right person".
"I lost three times until now and no one died, so it will be OK."- Halep, commenting on whether she's anxious about losing a fourth straight major final. If he wins the game, OK. I'm going to play Wimbledon, of course, and then I will have to analyse the situation afterwards, when I will be ready to play.
"I think also a good thing is that I faced him already twice here".
Nadal is only the third male player in the Open Era to reach 11 semifinals at a single Grand Slam, alongside Roger Federer and Jimmy Connors. The second set like, the first was dominated by serve until Cilic fired himself up to break at 4-4 - a furious Del Potro throwing his racket at the changeover. He missed the tournament every year from 2013-16 because of injuries, including three operations on his left wrist. As del Potro served, he was distracted by a noise from the crowd and double-faulted to lose the game.
"It's always hard playing someone from your country and such a good friend", Stephens said, "so I was really pleased to be able to get through that and play some good tennis". I tried to do too much.
Too good for almost everyone, nearly every time, on clay. Best of five is also a different story. Nadal continues to return at a high level, makes very little unforced errors and pounces the second his opponent gives him a chance to take control of the match.
After dropping the first two sets he played in the opening round, Cecchinato came back to win that match in five sets, then proceeded to string together upsets. He is 10-0 in French Open finals and 77-0 at the tournament overall when he wins the first set, so getting a jump on him early - a tactic far easier to write about than to execute - would seem to be a fairly obvious strategy. The only loss this clay court season has been to Thiem in the quarter-final of the Madrid Masters though he holds a 6-3 head-to-head advantage over the Austrian. Cecchinato was accused of match-fixing and suspended for 18 months in 2016, but he appealed, and his punishment was dropped on a technicality.
"Otherwise, it's not a very nice feeling".
Nadal acknowledged that Thiem has been a "very complex" opponent.
Thiem had to weather three set points for Cecchinato, at 7-6, 9-8 and 10-9. Thiem got to 10-all with a drop shot of his own.