And it wasn't even close -- Argentina scored in the third minute, and didn't look back.
Argentina's Lionel Messi had two assists and a brilliant free kick goal.
"You saw tonight why they are the number one team in the world," said U.S. head coach Jürgen Klinsmann. "It's just top class, what they're playing."
The third-minute goal off a corner kick. A U.S player slid to turn out a pass off the short corner but the ball went to Messi, who chipped to an unmarked Ezequiel Lavezzi. The Argentine forward nodded the ball over an uncertain U.S. goalkeeper Brad Guzan for a 1-0 lead.
But it's Messi's goal in the 32nd minute that everyone will be talking about.
After being fouled by Chris Wondolowski, Messi took a free kick that sailed over a U.S. wall, burying the ball in the top-left corner, just out of the hands of Guzan.
Messi broke Argentina's all-time goal scoring record with that goal.
The third goal came early in the second half when Gonzalo Higuaín slipped in past the U.S. backline. His initial effort was stopped by Guzan but he calmly knocked home the rebound. Higuaín also scored the final goal in the 86th minute off a Messi assist.
Lavezzi had a scary moment in the 62nd minute, when he fell over a wall out of bounds while going after a ball. He was taken off on a stretcher.
A step behind
Though the Americans had shown a lot of promise by reaching the semis, it was a tough night for them.
The United States looked a step behind the entire night, with bad passes and turnovers dooming the red, white and blue in the end.
"You play against a good team and they make you pay," U.S. midfielder Michael Bradley said.
The United States did not manage a shot on goal and possessed the ball only 33% of the time. Statisticians dubbed more than one-third of its passes "incorrect."
While the Americans played better in the second half, they had few good moments in the Argentine half.
"We let them dictate the pace of the game," Geoff Cameron told Fox Sports. "They got in a rhythm, they got that early goal, and it kind of shot us in the foot a little bit."
The Argentines did indeed dictate the pace of the game -- their possessions were clean and they clearly had a plan with what they were going to do with the ball on most plays.
"Once they have a lead they're not giving that lead away anymore," Klinsmann said. "They know exactly how to kind of organize themselves behind the ball quickly."