All the Americans needed was a win against a Panama team they've beaten soundly in the past - a team 32 spots lower than them in the FIFA rankings - and they would go through to the knockouts.
What followed was a game that might be nothing short of a national embarrassment - and could lead to a crisis of confidence in manager Gregg Berhalter.
The USMNT had some of its worst passing (116 total completed passes, 60 percent accuracy) and did not control possession in a game where the Americans were down to ten men within 20 minutes of action. It ended in a 2-1 loss that asks plenty of questions around this team and it's coach's ability to adapt to the game in front of them.
Now the Americans face the reality of potentially being eliminated from the Copa America entirely - likely needing a victory or a draw against Uruguay to advance - in a game where they'll be without a starter in Tim Weah.
They may also be forced to play without Matt Turner - their starting goalkeeper who suffered a leg contusion on a hard challenge early in the match.
Tim Weah was sent off in the 17th minute, contributing to a 2-1 loss in the Copa America
Questions will be asked about manager Gregg Berhalter's ability to adjust after this defeat
The Americans believed they got off to a hot start with a goal from Weston McKennie that came in the fifth minute. But after consulting VAR, referee Ivan Barton ruled that center back Tim Ream was offside when he put a header on keeper Orlando Mosquera.
A brief scare fell into the lap of the Americans in minute 12 when Cesar Blackman went for the ball and clattered into keeper Matt Turner. Turner landed awkwardly and stayed down for some time before eventually getting up and playing on.
The nightmare start continued in the 17th minute when starting winger Timothy Weah completely blew a gasket and punched defender Roderick Miller in the head.
After initially being given a yellow card, Barton reversed his decision and showed Weah a red card and sent him to hit the showers early.
With momentum on the side of Panama, it would have been expected that Los Canaleros would take advantage first.
But it was Folarin Balogun who netted the first goal of the night for the United States to take a 1-0 lead.
It was a sublime effort off some miscommunication with Gio Reyna. Reyna played a ball to the goal scorer who tried a one-two pass that bounced off the midfielder's ankle. The ball fell perfectly for Balogun who struck it cleanly and rocketed it onto the keeper's left post and over the goal line.
Matt Turner went down with a leg injury and played on through the rest of the first half
Things got worse after Tim Weah (21) was sent off for punching a player in the head
Luckily for the USA, Folarin Balogun (20) scored his second goal of the tournament to go up 1-0
If only the Americans could have made that lead stick.
It took just four minutes for Panama to equalize. Cesar Blackman's first shot was blocked, but his second attempt managed to deflect off Chris Richards and trickle past the diving arms of Turner to level the contest.
The first half ended with plenty of rough play that symbolizes CONCACAF football - but only Antonee 'Jedi' Robinson was handed a yellow card.
Manager Gregg Berhalter raised his arms incredulously in minute 43 when a ball over the top for Christian Pulisic resulted in what he thought was a clear-cut penalty in the box. Edgardo Farina horribly mistimed his aerial challenge and fell on top of the American captain, but Barton did not produce a card and did not call a penalty as Pulisic was offside.
At the half it was clear the USMNT was being utterly dominated. They were being woefully out-possessed and only completed 62 percent of their passes. That included only 26 total passes in the final 23 minutes.
Berhalter knew changes needed to be made and fast. Turner wasn't able to continue on after the half due to a leg contusion and backup keeper Ethan Horvath was brought in. In addition, off went Reyna and Tyler Adams for Cameron Carter-Vickers and Johnny Cardoso.
The American lead lasted just four minutes before Cesar Blackman equalized for Panama
But he also made the decision to sit back for a majority of the match to absorb pressure a la the Brazil game. It's a questionable decision considering the Americans should have been looking for a goal to break the deadlock.
After a probing ten minutes, the Americans held their breath after a penalty was called in the 62nd minute. On first look, it appeared that Carter-Vickers had tripped up Jose Fajardo in the box. But VAR showed that he hadn't touched the Panamanian attacker and play continued at 1-1.
Balogun tried one more attempt on goal in the 71st minute that sailed harmlessly past the post and he was replaced by Ricardo Pepi, who had unfortunate luck in the Bolivia game.
Nothing seemed to be working for the Americans as the game reached the 80th minute. Any attack saw Panama throw bodies in front of the ball preventing any buildup from happening.
The cleanest opportunity they had late in the game was in the 82nd minute when the snakebitten Pepi's header had no venom on it and the ball was cleanly taken by Mosquera.
Jose Fajardo of Panama (17) celebrates scoring the game-winning goal against the USMNT
With this loss, the USA will likely need a result against its toughest group opponent - Uruguay
Then came the back breaker. A lengthy spell of possession in the American half led to a cross to Fajardo in the box. He put a boot on it as it sailed right toward Horvath. The keeper got a glove on it and the ball sailed through both of his hands. 2-1 Panama.
CONCACAFiness ensued. Adalberto Carrasquilla went in with a wild challenge - lashing out at Christian Pulisic's legs and sending him to the ground. An immediate red card was drawn and both teams were even on ten men.
Still, the Americans could do nothing. Panama was able to dribble out the clock and the match ended with a victory that will have the United States with their backs against the wall in a do-or-die match against their toughest group stage opponent.