Sam Querrey and John Isner lost their opening singles matches Friday, giving the defending champions a 2-0 lead in the Davis Cup semifinals.
David Ferrer put the hosts ahead in the best-of-five series with a 4-6, 6-2, 6-2, 6-4 win over Querrey. Nicolas Almagro beat Isner 6-4, 4-6, 6-4, 3-6, 7-5 to leave Spain one point from its fourth final in five years.
Almagro overcame 25 aces from Isner, who saved three match points before hitting a forehand long.
The U.S. must win the doubles match Saturday to stay in the series, with brothers Mike and Bob Bryan facing Marcel Granollers and Marc Lopez. The Bryan twins are 4-0 when the U.S. has faced a 2-0 deficit, and 5-0 against Spain.
Reverse singles are Sunday. Spain is playing without injured Rafael Nadal, and the U.S. is without Andy Roddick, who retired after the U.S. Open.
The United States has only rallied back to win from a 0-2 deficit once in 38 series - in 1934 against Australia. Since the start of World Group play, Spain is 37-0 after winning both opening singles.
The winner plays either Argentina or the Czech Republic in the final in November.
Almagro and Ferrer are a combined 23-1 on clay. While Querrey wasted nine break opportunities in the fourth set of his match, Isner took advantage of his lone chance in the fourth to reach the deciding set.
As the light quickly faded, neither player relented on serve. Isner fired another ace to save a 16th break point before committing three unforced errors in the final game.
The 10th-ranked Isner had a 4-0 Davis Cup record this season, including wins over Roger Federer and Jo-Wilfried Tsonga. But the 6-foot-9 Isner dropped to 0-3 in five-set Davis Cup matches.
The fifth-ranked Ferrer started well with a break but eventually surrendered his only two service games of the match to lose the first set to Querrey.
Querrey, returning to Davis Cup play for the first time since 2010, failed to convert 12 break chances as the wind gusted off the Bay of Biscay.
"On a couple of them, I should have been more aggressive but he played good points," said the 26th-ranked Querrey. "I feel if I get one of those breaks, it could be a different game."
Ferrer played on hard courts in the U.S. Open semifinal on Sunday.
"It's never easy to adapt from hard court to clay, and with only three to four days even less," said Ferrer, who is 15-0 on clay in the competition. "I didn't feel too bad, but I didn't play perfect tennis, either."
Federer leads Swiss ahead
AMSTERDAM (AP) -- Top-ranked Roger Federer beat Thiemo de Bakker in straight sets and Stanislas Wawrinka defeated Robin Haase to give Switzerland a 2-0 lead Friday over the Netherlands in their Davis Cup World Group playoff.
Federer overcame wet and windy conditions on a temporary outdoor clay court in Amsterdam to beat the 159th-ranked De Bakker 6-3, 6-4, 6-4.
"On the serve, it can play tricks on you," Federer said of the gusty wind. "The ball, after you tossed it, it was moving away from you and you had to adjust the whole time. So to find a way to move the serve was pretty difficult."
Federer said the match probably wouldn't have started on the regular tennis circuit because of the rain, but he played down the conditions.
"It's OK, no problem," he said. "I mean, I'd prefer a sunny day, who wouldn't? But this is a challenge as well."
Federer's doubles partner Wawrinka had a tougher time against Haase, but won 6-3, 3-6, 6-3, 7-6 (4).
Federer and Wawrinka, the 2008 Olympic doubles champions, can wrap up the playoff Saturday by beating Haase and Jean-Julien Rojer in the doubles. Reverse singles are scheduled for Sunday.
Argentines, Czechs split openers
BUENOS AIRES, Argentina (AP) -- Argentina's injured and emotional Juan Martin del Potro beat Radek Stepanek in the opening match, and the Czech Republic's Tomas Berdych evened the Davis Cup semifinal by topping Juan Monaco in the second match Friday.
Del Potro, told by doctors not to play because of an inflamed left wrist, beat Stepanek 6-4, 6-4, 6-2, and then broke down crying as he addressed cheering fans at the outdoor clay-court venue. Stepanek suggested afterward that Del Potro might have exaggerated the injury in a bit of gamesmanship.
Berdych later rallied to edge Monaco 6-1, 4-6, 1-6, 6-4, 6-4, leveling the contest before the doubles Saturday and reverse singles Sunday.