Charles De Ketelaere set the tone in tonight's round of 16 in Seattle with a goal in the ninth minute.
"Everyone saw from the start that we didn't manage to get into the game," said US national team coach Mauricio Pochettino, according to AP.
The USA managed to equalise from a free kick half an hour into the match, but that was partly because Malik Tillman's shot bounced off Belgium's Hans Vanaken and into the net.
A minute later, Atalanta star De Ketelaere stepped forward again and headed in another goal to restore the lead.
Goalkeeper's brain drain
The away team dominated the first half in terms of chances and possession, but it was the US goalkeeper who helped the Belgians pull away with a poor decision in the middle of a breakaway.
Matt Freese left his penalty area to intercept a Belgian cross and succeeded, but in the next moment he lost his composure and the ball. De Ketelaere was able to poke it to Hans Vanaken, who shot it past Freese and into an empty goal in the 57th minute.
"We knew that if we put pressure on them, they would make mistakes," said Belgian captain Youri Tielemans after the match.
Belgium's centre forward Romelu Lukaku – who had started on the bench along with other stars Kevin De Bruyne and Jérémy Doku – put the game beyond doubt with a 4-1 goal in stoppage time.
Hand behind the ear
"Cancel this," reads a clear message from the Belgium national team on social media, with a picture of Lukaku holding a hand behind his ear and looking up at the stands in Seattle.
Leading up to the match, almost everything had been about Folarin Balogun. The US forward was not expected to play in the round of 16 after he was sent off in the round of 16 against Bosnia-Herzegovina.
The suspension was lifted in a surprise decision by FIFA. US President Donald Trump said he had called FIFA President Gianni Infantino to resolve the matter, which has been followed by enormous criticism and new allegations of corruption against a long-questioned FIFA leadership.
Folarin Balogun did not make a big impression in the match and was substituted in stoppage time, just before Belgium's fourth goal.
“Not an excuse”
The US national team coach does not see the controversies surrounding the suspension as having affected the match.
"It's not an excuse and we can't make excuses. It wasn't our day," Mauricio Pochettino told AFP.
Belgium next faces Spain, who earlier on Monday knocked out Portugal with a goal in overtime.
