Jurgen Klinsmann entered Tuesday’s match against Costa Rica under more pressure than at any point in his near five years in charge of the United States men’s national team. A defeat and the U.S., as host, would have faced the ignominy of becoming the first country to exit the Copa America Centenario. If Klinsmann wasn’t already aware of the seriousness of the situation, his boss Sunil Gulati ratcheted up the heat on the morning of the game, saying “We have to win games” and that “No one has ironclad job security.”

Given those conditions, perhaps not even Klinsmann, the eternal optimist, could have envisioned how comfortable Tuesday night at Chicago’s Soldier Field would turn out to be. The result was effectively sealed before halftime, with the U.S. going 3-0 up against its Concacaf rival before a goal from substitute Graham Zusi put the lock on an emphatic win. Bottom of the group at the start of the day’s play, by the end the U.S. was in a strong position to clinch a spot in the quarterfinals. A draw against Paraguay on Saturday and, barring a massive win for Costa Rica over Colombia, the U.S. will be in the knockout phase.

“I think we are right there in the driver’s seat to get through this very, very difficult group. This is the most difficult group in the Copa America,” said Klinsmann.

Yet, despite the improvements from an opening loss to Colombia, it would be dangerous to believe that the hard work has been done and the corner turned. While the scoreline was emphatic for the U.S. in Chicago, Klinsmann’s side wasn’t always so dominant over the course of the 90 minutes. Costa Rica began the better and had a chance fired wide from Arsenal forward Joel Campbell. Indeed, even Klinsmann conceded afterward that his side was shaky in the first 15 to 20 minutes.

The difference was the greater sharpness in the final third from the U.S., as it scored three goals from its five shots on target, helped by some less-than-proficient goalkeeping. And then there was a dominating, age-defying performance from 34-year-old Jermaine Jones.

Going into the Paraguay game, though, questions remain for Klinsmann. The biggest of those is which formation best suits the players at his disposal. Late in the first half against Costa Rica, he switched from the 4-3-3 with which he began the tournament, and it paid immediate dividends. Moved into a central striker position where he's far more comfortable, Bobby Wood almost instantly struck the third goal. And it came from an assist from Clint Dempsey, who again demonstrated he can be more effective with a striker in front of him.

Yet a 4-4-2 leaves Jones and Michael Bradley as the central midfield partnership, a combination that has never been entirely natural. Early in the second half, the U.S. again lost some control and it would be something of a risk to field them in a "must-not-lose game."

For all the positivity of the result against Costa Rica, the Yanks find themselves back in the position of knowing that a defeat will mean an early exit. And Paraguay showed enough, even in a 2-1 defeat, against Colombia to suggest that there could be a few nerves Saturday in Philadelphia.

After being thoroughly outclassed in the first half by a thrilling Colombia, Paraguay went with a more positive game plan in the second and came close to snatching a point, despite a red card for Oscar Romero that will now keep him out of the match with the U.S.

The good news for the U.S., as it seeks to avoid disaster, is that Paraguay have not won in five games in 2016.