MAR DEL PLATA, Argentina—Spain's 5-7, 7-5, 7-6, 6-3 win over Argentina in Saturday's Davis Cup doubles rubber put the visiting team one point shy of its third Davis Cup victory and signaled that Spanish tennis is about much more than just world No. 1 Rafael Nadal.

On paper, the Spaniards should struggle to lift the Cup on Sunday, with two rubbers in a hostile arena against players that in any other circumstance would be considered the favorites. But Feliciano Lopez's upset against Juan Martin del Potro Friday puts Sunday's match in doubt, especially because the Argentine’s physical condition is unclear.

Del Potro is scheduled to play David Ferrer, whom Nalbandian beat handily Friday, and Nalbandian would play Lopez, who beat an ailing Del Potro. Argentinean coach Alberto Mancini said he hadn't yet decided whether to replace Del Potro, who was said to be suffering from severe cramps; Spanish coach Emilio Sanchez-Vicario also said he would make the decision later on whether to substitute for either Lopez or Ferrer.

Substitutions are allowed nearly up to match time.

Ferrer has struggled recently and turned in a somewhat lackluster performance against a brilliant Nalbandian, while Lopez has now played long matches on consecutive days.

Following Saturday’s doubles match, an angry Nalbandian went back to his team's hotel, skipping the obligatory post-match press conference. Mancini said he was sick both physically and emotionally. The International Tennis Federation's referee will assess a fine of up to $10,000 for the no-show, an ITF official said.

Guillermo Vilas, the former world No. 2, said before the match Saturday he thought losing the doubles point would be worse for Spain than Argentina. Vilas also alluded to the tie's importance, saying that a new "explosion" in tennis would occur with a win and could energize Argentina's youth.

The Argentinean fans did all they could to distract Lopez and Verdasco Saturday; at one point, when the Spaniards were serving, the exacerbated chair referee looked to Argentina's coach for help quieting the crowd.

Sanchez-Vicario, who on Friday complimented the spectators on their respectful demeanor, said his opinion changed during the doubles.

"Today I'm disillusioned," said Sanchez-Vicario, adding that Argentinean fans had shouted expletives during serves and points.

Verdasco said the crowd’s hostility did not bother him.

"Everything they screamed at me, it just made me more motivated," he said.

The match, which lasted 3 hours and 18 minutes, featured more nerves and squandered opportunities than shot-making. The Spanish team served for the third set at 5-1, only to let the Argentineans level the set – and the match -- at 6-6. In the tiebreak, it was the Argentineans who went up 5-1, only to lose six consecutive points and the third set.

Despite the doubles loss, Vilas thinks Argentina has a good chance Sunday. He reminded reporters that the crowd is desperate to see Argentina win its first Davis Cup, and thinks that will work to the hosts’ advantage.

Less optimistic was Norma Baylon, a Top 5 player in the 1960s who now works with the Argentinean tennis federation. Baylon said home-court advantage is no advantage at all for the players representing the blue and white.

"In Spanish they say, 'we are in the oven,'" she said. "They have too much pressure."