Verdasco and Lopez withstood the fierce support for the hosts
Spain took charge of the Davis Cup final in Argentina thanks to victory for Feliciano Lopez and Fernando Verdasco in Saturday's doubles rubber.
The Spanish pair defeated David Nalbandian and Agustin Calleri 5-7 7-5 7-6 (7-5) 6-3 to give their side a 2-1 lead in the best-of-five tie.
A passionate crowd in Mar del Plata could not stop Spain and the tie comes down to Sunday's reverse singles.
Juan Martin del Potro is scheduled to open against David Ferrer.
However, the Argentine is a doubt with a thigh injury and his absence would seriously dent the home side's chances of a first Davis Cup win, while Verdasco could be preferred to Ferrer for Spain.
Argentina captain Alberto Mancini said the hosts were feeling the heat after going into the final as favourites.
"The boys are under a lot of pressure and it's not easy to deal with," he said.
When the crowd express themselves in a manner which lacks respect, they lose all the credibility they had gained until now
Spain captain Emilio Sanchez Vicario
"All the matches have been very even. I think we had a little bit of bad luck."
Nalbandian left the stadium after the doubles defeat without attending the scheduled press conference, which will lead to a fine of up to US$10,000.
The match hinged on a dramatic third set where Spain raced to a 5-1 lead before Argentina hit back to force a tie-break.
Argentina then led 5-1 in the tie-break before the Spanish won six points in a row to take the set.
"It was tough to go 5-1 up and then go to a tie-break, it was tough mentally, but that was the key," said Verdasco. "After that we played better and much looser."
Lopez added: "It was virtually a miracle how we won that tie-break.
"It was unforgettable to play with the crowd singing like this. Even though they were supporting Argentina, it was very enjoyable to play in."
However, Verdasco and Spain captain Emilio Sanchez Vicario were less than pleased by some offensive chanting.
"I didn't do anything to the crowd, it was them who turned against me," said Verdasco.
"It gave me more motivation, it increased my desire to win and helped me find more strength. I played better after they started insulting me."
Sanchez Vicario added: "It was a little disappointing, this is a sporting event and the winner is decided by what happens on the court.
"When they express themselves in a manner which lacks respect, they lose all the credibility they had gained until now.
"When you see so many people using words which I won't repeat here... it's something you don't expect from an educated public which understands tennis."
Lopez had brought Spain back into the tie on Friday with a superb singles win over Del Potro, after Nalbandian had beaten Ferrer.
World number one Rafael Nadal is not playing for Spain after his season ended with a knee injury two weeks ago.
The tie is being played on a fast indoor court, originally chosen to try and neutralise the threat of Nadal.
Argentina are seeking their first Davis Cup title, having finished runners-up away to the United States in 1981 and Russia in 2006.
Spain won the Davis Cup in 2000 and 2004, but lost three times as visitors in 1965, 1967 and 2003 - each time against Australia.