For this match to not go the USA's way, it has to really not go the USA's way. Ideally, the Americans want to win or tie the game and advance to the 2017 CONCACAF U-20 Championship final for a shot at their first-ever regional title at this level. (For real: the USA has never won the regional Men's U-20 title.) But first and foremost, the US U-20s want to qualify for the 2017 FIFA U-20 World Cup.
After Mexico thrashed El Salvador in the preceding game of this Classification Stage group, the USA's qualification for the U-20 World Cup is essentially a formality. The Americans will advance to the FIFA tournament in South Korea even with a loss to El Salvador, it just has to be a loss that doesn't hand the Salvadorans a tiebreakers advantage in the group - and that would need to be a loss by three goals or more.
"Don't lose by three goals" seems an achievable ambition for the USA in this match. The Americans have been beaten at this tournament, but have never looked in danger of being thrashed. It will be a big surprise if the US U-20s - and the New York Red Bulls Tyler Adams - don't emerge from this game without some measure of success, even if they lose.