The United States booked their place in the semi-finals of the CONCACAF Nations League on Monday despite slumping to a 2-1 defeat away to Trinidad and Tobago.

The defending Nations League champions advanced with a 4-2 aggregate victory but made Monday's second leg in Port of Spain harder than it needed to be after self-destructing just before half-time.

Gregg Berhalter's side had picked up where they left off in last Thursday's home game, which they won 3-0, dominating Trinidad and Tobago from the outset and creating a string of early openings.

Brenden Aaronson saw a shot well-saved by Trinidad goalkeeper Denzil Smith in the opening minutes, and Folarin Balogun also saw a promising shot blocked by the home keeper in the fourth minute.

The early US dominance got its reward on 25 minutes when right back Sergino Dest swung a pinpoint cross into the area and defender Antonee Robinson stooped low to head home for 1-0.

But the game was turned on its head in the 39th minute after a moment of madness from Dest. 

The US defender was booked by referee Walter Lopez after kicking the ball away petulantly, and then picked up a second yellow card after continuing to harangue the Guatemalan official.

Stand-in skipper Tim Ream and goalkeeper Matt Turner both lambasted the dismissed US defender as he trudged off following a needless tantrum.

That flashpoint clearly rattled the Americans, and Trinidad got back into the game when Reon Moore latched on to a through ball two minutes before half time and crashed a ferocious first-time shot high into the net past Turner's near post.

Although Trinidad struggled to generate many clear chances after restart, the Soca Warriors took the lead on 57 minutes after a free-kick from Alvin Jones. 

Jones' set piece from outside the area was well-struck, but US goalkeeper Turner should have done better, attempting to punch the ball clear but only succeeding in deflecting it into his own net.

Trinidad though never looked like scoring the three additional goals they needed to pull of a mammoth upset, and team USA held on to seal an aggregate victory that also assures them of a place in next year's Copa America.

"Disappointed we didn't get the win," US goalscorer Robinson said afterwards. "We started the game pretty well and had things under control and then a moment of unprofessionalism kind of went against us.

"But we'll take it," he added. "We're in the semi-finals of the Nations League and we're in the Copa America, so it's still been a successful break."

rcw/mlm