The United States will aim to exploit the mile-high mountain air of Colorado on Thursday when they host Trinidad and Tobago in a key 2018 World Cup qualifier in Denver.

After a sluggish start to the final round of CONCACAF qualifiers, the Americans remain just outside the automatic qualifying places with only four points from four games.

Back-to-back opening defeats against Mexico and Costa Rica led to the dismissal of Jurgen Klinsmann last year and left the Americans with little margin for error in their remaining fixtures.

Three points against Trinidad and Tobago's "Soca Warriors" will be the minimum requirement for Bruce Arena's men before they depart for a daunting assignment with bitter regional rivals Mexico at the Azteca Stadium on Sunday -- a game that will also be played at altitude.

The US, who have played in every World Cup finals since 1990, have spent the past fortnight training at altitude in Colorado and Utah, as they chase the points that will vault them into the automatic qualifying positions.

Borussia Monchengladbach midfielder Fabian Johnson admitted players had been left gasping during the training camp.

Mexico lead the standings with 10 points from four games but will be wary of the threat posed by Honduras, who scored a 2-1 victory at the Azteca in a 2013 qualifier.