There was good reason for Jurgen Klinsmann to label the United States men's national team's game against Colombia on Friday a "final."

After all, the Yanks weren't just facing one of the strongest teams in the Copa America Centenario and the favorites to win their group, but also the prospect of going into the remainder of their Group A contests in a bad way. Lose that first game and the margin for error would be whittled down to the approximate width of a fishing line.

[ USA vs. Costa Rica Live | Match stats | Three things to watch for ]

The Americans did lose, 2-0, in fairly simple fashion, and now that margin is a sliver.

Which means that just one game into the biggest tournament the U.S. has played stateside since the 1994 World Cup, Klinsmann's men are already relegated to math and prognostication as they match up against a familiar foe in Chicago on Tuesday – Costa Rica. The Ticos, by the way, went to the World Cup quarterfinals in 2014 and beat the U.S. 1-0 the last time they played, back in October.

[ Copa America Centenario | Scores and Schedule | Standings | Teams ]

"It's a must-win situation. We've gotta get it done tomorrow night," Klinsmann told reporters on Monday. "They have one point and we have zero points, so we had better get the first three and find ways to do that. … We know we have our backs against the wall. We need points in order to have a good position for our last game [against Paraguay] in Philadelphia [on Saturday]."

Indeed, for that Paraguay game to even be relevant, the Americans – at the very least – need a tie. A loss and they're eliminated with a game to spare. And even if they manage a draw, they'll probably need Colombia to beat Paraguay in the other game to keep hope alive for the final match – when they would need a win and help.

Costa Rica stands in the way of the Americans, who have faced the Ticos 16 times since 2000 going 6-7-1. The U.S. is 13-14-6 against Costa Rica all-time – the Yanks' record was positive until the last two games happened. But they'll take heart in knowing that their record on home soil is a stout 13-5-4.

The Costa Ricans are without star goalkeeper Keylor Navas and his understudy Esteban Alvarado, relegating them to third-stringer Patrick Pemberton, and they are just as much in trouble as the U.S. If not more. After all, they tied Paraguay 0-0 in their first game and now face the hosts and then Colombia.

Costa Rica has been mercurial since the highs of the World Cup, with form fluctuating wildly. But a constant has been its sound defense. In their last 14 games, the Costa Ricans have given up just six goals – and never more than one in a game. And it just so happens that the Americans struggled to create chances – let alone convert them – against Colombia.

On Friday, the Cafeteros realized fairly quickly that their early goal would likely hold up against an American attack that was unmoored from its midfield – that Clint Dempsey, Bobby Wood and Gyasi Zardes would struggle to score on them. And so they spent most of the game coasting or idling, letting the Americans drive the game forward.

This gave the U.S. the impression that they had played the Colombians evenly, and the statistics did indeed bear out an edge in shots and possession.

"We believe really that we had a good start, besides the result obviously," Klinsmann said on Monday. "The performance was a good performance. … We played one of the top teams in the world the other night and we gave them pretty much nothing."

His players have sounded equally upbeat about the game.

But this assessment overlooks the disinterest the Colombians showed in getting out of second or third gear once they doubled their lead on a cheaply acquired penalty before halftime. Colombia simply let the Americans come at it, and the Yanks struggled enormously to locate the seams or find much room at all in the final third.

Absent the injured Jozy Altidore, Klinsmann is basically playing all three of his forwards out of position and it shows. This, of course, is par for the course under Klinsmann's haphazard tenure, but he sounds disinclined to tinker with his front line at this point.

In midfield, fans have clamored for the promotion of playmaker Darlington Nagbe to the starting lineup in order to add a little attacking endeavor to the middle. But Nagbe's deployment would have to come at the expense of either Alejandro Bedoya or Jermaine Jones, who both do yeoman's work in front of the now deeper-sitting Michael Bradley.

It's a complex puzzle. One that Klinsmann perhaps should have solved months – if not years – ago, rather than forever overhauling his lineups and experiment with new players. But here we are. Another loss would end the Americans' Copa just four days after it began.

"It's a very tough Costa Rican team," Klinsmann said. "Hopefully we find ways to break them down to get the first three points, which we obviously badly need."

Leander Schaerlaeckens is a soccer columnist for Yahoo Sports. Follow him on Twitter @LeanderAlphabet.