Mariano Navone downs champion Cameron Norrie with ease to reach ATP Rio Open final
British No.1 Norrie - aiming to win back-to-back titles in Rio after defeating Carlos Alcaraz in last year's final - struggled in hot and humid conditions before sliding to a 6-4, 6-2 defeat.
Navone, currently ranked 113th in the world, was handed three match points when Norrie smacked a forehand long in the eighth game of the second set.
Another miscued return by the second-seeded British world number 23 sealed victory for the Argentine youngster, who advances to the first ATP final of his career, where he will face compatriot Sebastien Baez.
"It's incredible, my first final," Navone said after the win. "I played so good all week. Today was very hot and humid, it's tough to play in these conditions.
"But I've played six matches in a row so I feel pretty good."
Navone's victory set up an all-Argentina clash in Sunday's final on the Quadra Guga Kuerten showcourt after Sebastian Baez defeated compatriot Francisco Cerundolo in Saturday's other semi-final.
Baez saved three set points in the first set of his clash with Cerundolo before going on to win 7-5, 6-0.
"We know each other too much, I think, more than I want," Baez said after his semi-final win. "All matches are different. Today it's going to my side.
"In the first set, I gave many break points to him. I had to take it because it's so hard for both."