(AP) -- They captured the eyes and hearts of a suddenly awakened soccer nation, who gathered in unprecedented numbers to watch the world's game.

But the end of the ride came at the exact same point as four years ago: with a loss in extra time in the World Cup's round of 16.

Belgium scored twice in extra time then held on for a 2-1 win Tuesday.

"It's heartbreaking," goalkeeper Tim Howard said. "I don't think we could have given it more."

Howard, playing the finest game of his career, stopped a dozen shots with his legs and arms to keep the Americans even through regulation and force an additional 30 minutes. He wound up with 16 saves -- the most in the World Cup since 1966.

Before exiting, the U.S. showed the spunk that won America's attention. Julian Green, at 19 the youngest player on the U.S. roster, stuck out his right foot to volley in Michael Bradley's pass over the defense in the 107th minute, two minutes after entering the game.

The Americans nearly tied it up in the 114th, when Clint Dempsey peeled off the ball and was fed by Bradley on a free kick, but he was stopped point-blank by goalkeeper Thibaut Courtois.

At the final whistle, the U.S. players fell to the field in their all-white uniforms like so many crumpled tissues.

"I think they made their country proud with this performance," coach Jurgen Klinsmann said.

The Americans advanced from a difficult first-round group that included Germany, Portugal and Ghana to reach the knockout rounds of consecutive World Cups for the first time. Four years ago, they were eliminated in South Africa by Ghana 1-0 on a goal in the third minute of extra time.

Fans who had made the trek south of the equator chanting "I believe that we will win!" could hardly believe they lost, extending a World Cup winless streak against European nations to nine games over 12 years.

The crowd of 51,227 at Arena Fonte Nova appeared to be about one third pro-U.S., with 10 percent backing the Belgians and the rest neutral. Back home, millions watched in offices, homes and public gatherings that included a huge crowd at Chicago's Soldier Field.

"There's a lot to build on going forward," Klinsmann said.

President Barack Obama joined about 200 staffers in an Executive Office Building auditorium to watch the second half.

"I believe!" he exclaimed as he walked in at the front of the hall. "I believe!"

In its first World Cup under Klinsmann, the U.S. had promised to play attacking soccer. But once again the Americans had trouble maintaining possession and for much of the night it seemed as if the field were tilted.

The 35-year-old Howard kept saving his team. Belgium had 38 shots to 14 by the U.S.

But when Matt Besler lost his balance on an attack down the right, Romelu Lukaku sped in alone and crossed in front of the goal. The ball rebounded off defender Omar Gonzalez, and Kevin De Bruyne controlled it, spun and beat Howard just over his right foot in the third minute of extra time.

Then with the U.S. pushing for an equalizer 12 minutes later, De Bruyne burst ahead and fed Lukaku. He slotted the ball past Howard, his Everton teammate, for a 2-0 lead that seemingly put the game out of reach.

But Green, among five German-Americans on the U.S. roster and a surprise pick, woke up the team and its fans with his first touch, setting off raucous chants of "U-S-A! U-S-A!" There would be no final comeback this time, though.

"You get to this point and these games are always about a play here and play there," Bradley said.

Chris Wondolowski had a chance to win it in stoppage time when Jermaine Jones flicked the ball to him at the top of the 6-yard box, but with Courtois coming out Wondolowski put the ball over the crossbar.

U.S. forward Jozy Altidore, who strained his hamstring in the World Cup opener, did not play again. Klinsmann had announced Monday he would be available, but the coach said after the game the forward wasn't quite ready.

"The dream falls short, but this is an incredible group," Howard said, "and we'll never forget this night."