Carlos Berlocq defeated Frenchman Gilles Simon on Sunday in the deciding singles match to put Argentina into the Davis Cup semifinals.
Berlocq won 6-4, 5-7, 6-4, 6-4 to delight the rowdy crowd at Parque Roca, the outdoor clay-court venue on the outskirts of the Argentine capital.
Jo-Wilfried Tsonga of France defeated Juan Monaco 6-3, 6-3, 6-0 in Sunday's first singles to force the decider following Argentina's victory in Saturday's doubles.
It was Argentina's first victory in six tries against France in Davis Cup play.
"I have no words to say how I feel," Berlocq said. "You can't imagine how frightened I was when I took the court to start the match."
Argentina will play away against the defending champion Czech Republic in the semifinals later this year. The Czechs defeated Argentina in Buenos Aires in last year's semifinals en route to the title.
Simon, who was playing for the injured Richard Gasquet, lost both of his singles matches as the Argentines were able to upset the favored French. Gasquet withdrew with an injured right ankle.
Argentina was also shorthanded, playing without top star Juan Martin del Potro, who skipped the series to focus on the ATP tour.
Berlocq took command in the fourth set when he broke Simon in the sixth game to lead 4-2. Leading 5-2 with Simon serving, Berlocq had three match points but failed to convert any of them. Simon then broke Berlocq in the ninth game to close to 5-4.
Berlocq closed it out in the 10th game, again breaking Simon and winning on his sixth match point in just under four hours.
"I feel like this was quite a feat," Berlocq said.