A thrilling doubles win by Mike Bryan and Mardy Fish kept the United States' hopes alive in their Davis Cup semi-final against Spain on Saturday.
The holders, who trailed 2-0 after the opening day, still need to win both of Sunday's singles to reach the final.
But Spain would have completed a whitewash were it not for a battling display in Madrid by Bryan and Fish.
They eventually saw off Feliciano Lopez and Fernando Verdasco 4-6 6-4 6-3 4-6 6-4 after a topsy-turvy match.
Fish was only playing in the doubles because of a shoulder injury to Bryan's usual partner, his brother Bob.
But after a hesitant start that saw Lopez and Verdasco take the opening set, he proved to be a strong partner.
The US duo seemed to have the match under control after winning the next two sets and going a break up at the start of the fourth but Spain rallied again to take the match to a decider.
Despite their eventual defeat, Spain remain heavy favourites to progress.
The reverse singles see world number one Rafael Nadal play Andy Roddick, who he beat in the 2004 final, and David Ferrer face Sam Querrey.
Nadal survived an early scare against Davis Cup debutant Querrey before winning in four sets in Friday's opener.
The French Open and Wimbledon champion initially struggled to contain Querrey's powerful serve and forehand and had to recover from the initial shock of being put on the back foot by an opponent just out of his teens.
The 20-year-old took the first set on a tie-break but Nadal fought back to win 6-7 (5-7) 6-4 6-3 6-4.
Never in my life have so many service points been scored against me on clay
Rafael Nadal
The world number one said after the match: "Never in my life have so many service points been scored against me on clay.
"It was very difficult for me to return balls and control points. It was very tough today."
In Friday's second match world number five Ferrer rallied to beat world number eight Roddick 7-6 (7-2) 2-6 1-6 6-4 8-6.
Ferrer was two sets to one down but made a crucial break in the fourth set to draw level before edging a close final set.
In the other semi-final, last year's losing finalists Russia also needed an epic doubles win to keep their tie with Argentina alive.
Igor Andreev and Juan Martin Del Potro eventually overcame David Nalbandian and Guillermo Canas 6-2 6-1 6-7 (9-11) 3-6 8-6 in Buenos Aires to reduce Argentina's lead to 2-1.
On Friday, Nalbandian had swept Andreev aside to claim a 7-6 (7-5) 6-2 6-4 win but Del Potro's victory over Nikolay Davydenko was even more one-sided, the 19-year-old dropping only seven games against the world number six on his way to a 6-1 6-4 6-2 win.
Nalbandian faces Davydenko and Del Potro takes on Andreev in Sunday's reverse singles.
Elsewhere in the Davis Cup, Roger Federer and Stanislas Wawrinka teamed up for the first time since winning Olympic gold in Beijing to clinch Switzerland's place in the elite World Group.
They beat Belgium's Xavier Malisse and Olivier Rochus 4-6 7-6 (8-6) 6-3 6-3 on Saturday, giving the Swiss an unassailable 3-0 lead.
Individually they had got off to a perfect start on Friday, as world number nine Wawrinka eventually beat 58th-ranked Steve Darcis 6-7 (4-7) 6-1 6-3 2-6 6-4 in the first singles match.
US Open champion Federer then saw off world number 95 Kristof Vliegen 7-6 (7-1) 6-4 6-2.