Rafael Nadal upset Andy Roddick 6-7 (6), 6-2, 7-6 (6), 6-2 and gave Spain a commanding 2-0 lead over the US in the Davis Cup final on Friday.
In the first singles, Spanish No. 1 Carlos Moya beat Mardy Fish 6-4, 6-2, 6-3.
The sweep puts Spain on track to win its second Davis Cup, adding to the title won in 2000 over Australia in Barcelona. The Americans have won the Davis Cup a record 31 times, but have not taken the team championship since 1995.
Only one team in Davis Cup history has come back from 2-0 down and won the final -- Australia in 1939 in a win over the Americans.
In Saturday's doubles, American twins Bob and Mike Bryan face Nadal and Tommy Robredo, who can clinch the best-of-five series. The Bryans, who are 4-0 in Davis play and have not lost a set, must win to keep the final alive into Sunday's reverse singles, where Moya was slated to face Roddick, and Fish against Nadal.
The 18-year-old Nadal was sensational on the slow, red clay on a chilly day at Olympic Stadium. He combined power on his sweeping left-handed groundstrokes with touch on repeated drop shots that even Roddick applauded with his racket.
"I had cramps at one point but I got through it," Nadal said.
Asked if he was ready to play on Saturday, he replied: "Right now, I'm not. I'm really beat. But I think I'll be ready tomorrow."
Officials said 27,200 tickets were sold, a record for a "sanctioned" tennis match. The old mark was set in 1954 in Sydney, Australia, when 25,578 watched the US defeat Australia in the Davis Cup final.
Roddick called the playing atmosphere "crazy."
"It was unlike anything I have experienced before."