I thought all USA needed to clinch a spot was a draw in either of the next 2 games. A draw would put the USA at 17 points, and Costa Rica has 12 points, so if they won their last 2 and USA drew and lost, and Mexico and Honduras both end up with more than 17 points (Mexico has 15, Honduras 13), then USA would still finish 4th. If USA draws to finish with 17, and Costa Rica fails to win 1 of their 2 last games, the most points they can end up with is 16.