Assuming that both Jamaica and the United States pick up three points each in their respective matches against group bottom-feeder Antigua and Barbuda, both Jamaica and the U.S. would be assured of ten points in group play.
In that scenario, if Jamaica were to beat Guatemala, they would finish the group with 13 points. The U.S. would enter its final match against Guatemala with ten points and Guatemala would remain at seven points.
Guatemala would then have to beat the United States by at least three goals to finish with a better goal differential than the U.S. to guarantee advancement. In this scenario, a tie by the U.S. would also guarantee its advancement. There is another messy scenario where Guatemala beats the U.S. by two goals and advancement comes down to tie-breakers.
In the same scenario of both Jamaica and the United States winning their respective games against Antigua and Barbuda, but Guatemala beating Jamaica, Jamaica would finish the group with ten points and the U.S. and Guatemala would both enter their October 16 game with ten points.
In this scenario, a tie would send both the U.S. and Guatemala through to the next round. A loss by either team in that game would send advancement between the loser and Jamaica down due to goal differential.
The bottom line is the U.S. can advance with two wins or a win and a tie. If the U.S. loses either game, it is very likely advancement will come down to goal differential.