Top seed Rafael Nadal swept past Argentina's Juan Martin del Potro in brilliant style to set up a US Open final against Kevin Anderson.
The Spaniard won nine games in a row at one stage on his way to a 4-6 6-0 6-3 6-2 victory in the second semi-final.
Nadal, 31, will try for a third US Open and 16th Grand Slam title on Sunday, against a surprise opponent.
South African Anderson, 31, beat Pablo Carreno Busta of Spain 4-6 7-5 6-3 6-4 earlier on Arthur Ashe Stadium.
At 32 in the world, Anderson is the lowest-ranked man to reach a singles final at Flushing Meadows since the ranking system was introduced in 1973.
He faces a huge challenge against Nadal, who has a 4-0 record in their head-to-head and grew stronger as the match wore on against a tired Del Potro.
"It means a lot," said Nadal. "It has been an amazing season of course after a couple with injures and troubles.
"To be back here in front of this amazing crowd, on this amazing court, and to have the chance to fight for another title is so important to me."
The last time Nadal lost a Grand Slam semi-final was against Del Potro on the same court eight years ago, and he was not about to endure a repeat performance.
After losing a tight first set, the Spaniard hit a rich vein of form, dropping just five more games, dominating on serve and ending the match with 25 forehand winners.
"I changed a couple of things after the first set," added Nadal.
"I was playing too much to his backhand and I knew that I had to change and move him more and be more unpredictable. It worked really well and I am very happy."