Never one to panic, never liable to have a letdown, Nadal hung tough, waited for 24th-seeded Matteo Berrettini to wilt ever so slightly and then pounced.
Nadal moved closer to a fourth US Open championship and 19th Grand Slam title overall — one away from Roger Federer's record for men — by pulling away for a 7-6 (6), 6-4, 6-1 victory over Berrettini under the roof at Arthur Ashe Stadium on Friday night.
The second-seeded Nadal was down 4-0, then 5-2, then 6-4 in the opening tiebreaker before taking the next four points and was on his way.
"You don't want to be in a tiebreak against a player like Matteo. ... I was a little bit lucky, no?" Nadal said. "I survived at that moment and ... after that, the match completely changed."
Sure did. Nadal broke once in the second set and three times in the third, while never facing a single break point in the match.
The 33-year-old Spaniard will face No. 5 seed Daniil Medvedev of Russia on Sunday.
It is Medvedev's first major final, Nadal's 27th. They've played each other once before, the final of the Montreal Masters hard-court tournament in August, and Nadal won 6-3, 6-0.
"He's one of the more solid players on tour," Nadal said. "He is making steps forward every single week."
Medvedev advanced earlier Friday by beating Grigor Dimitrov 7-6 (5), 6-4, 6-3.
The 23-year-old Russian first made a name for himself at the U.S. Open by earning the wrath of spectators. During his on-court interview, Medvedev referenced his "tournament of controversies," which included accumulating $19,000 in fines and antagonizing booing fans last week, saying he knew it was "not going to be easy with the public."
Medvedev's tennis was a bit scratchy Friday, and like Nadal, he barely avoided dropping the opening set. But he did just enough with his mostly defensive style to get past Dimitrov, who had eliminated Federer in a five-set quarterfinal.
"I do think he was better player in first set. I do think I was kind of lucky to win it," Medvedev said about Dimitrov. "Then the momentum changed completely. I think after, I was playing better than him in the next two sets."