Argentina lead France 2-1 in their Davis Cup World Group quarter-final tie after David Nalbandian and Horacio Zeballos came from behind to win Saturday's doubles.
French duo Julien Benneteau and Michael Llodra took the first set but Nalbandian and Zeballos fought back to clinch the match 3-6, 7-6 (7/3), 7-5, 6-3 to give the hosts the upper hand ahead of Sunday's reverse singles.
The teams were all square after Argentine Juan Monaco had levelled the tie following Jo-Wilfried Tsonga's victory over Carlos Berlocq on Friday.
Monaco is set to face Tsonga in the opening singles on Sunday, with Berlocq up against Gilles Simon.
Argentine captain Martin Jaite said: "Tomorrow the match remains very open. We've got the advantage, we've got to get just one point, while they need two. Both singles will be very competitive. We're leading, let's hope we can win.
"Horacio and David were excellent. It was a lovely day with a really important victory. We've got a real Davis Cup team."
"We wanted to put our teammates in the best possible position for Sunday but we didn't succeed," said Benneteau.