Three days ago, the U.S. under-23 national team had set its sights on London. Today, as the Americans prepare for a must-win match against El Salvador, they’re just hoping for a flight to Kansas.

There isn’t much room for error in these compact CONCACAF qualifying tournaments, and thanks to a 2-0 loss to Canada on Saturday, Caleb Porter’s charges have none left in their quest for a berth in this summer’s Olympic Games.

Ahead of the group finales, the Americans are in third place, a point behind Canada and El Salvador. Assuming Canada gains at least a draw against pointless, goal-less Cuba in the early game, the United States must defeat the Salvadorans in Nashville to secure passage to Saturday’s semifinals at Livestrong Sporting Park in Kansas City, Kan.

Even if they advance, they’re staring at a weekend showdown with Mexico, which has rolled through Group B with victories over Trinidad & Tobago, 7-1, and Honduras, 3-0. (Not that Honduras is an easy opponent either — the Americans defeated the Catrachos in group play in each of the previous three qualifying tournaments but lost to them later in the event, albeit in matches after the Olympic berths were decided.)

Group obstacles are nothing new to the United States. In 2000, there was a 0-0 draw with Canada in the second game. Four years later, a pair of 4-3 victories preceded a 4-0 semifinal loss to host Mexico. And in 2008, the campaign began with a 1-1 draw against Cuba and proceeded with 1-0 victories.

Roster credentials provide the Americans with a decided advantage against El Salvador (9 p.m. ET, Universal Sports Network, mun2,,, but needing a victory is much different than needing a draw -- which is all El Salvador requires to advance.

A scoreless match at halftime would undoubtedly heighten the Americans’ urgency and anxiety. When they found themselves in a tight spot Saturday, they didn’t respond well. The attack sputtered all night and defensive shortcomings on set pieces led to the first defeat to Canada in 20 years: goalkeeper Bill Hamid failed to harness a corner kick within reach and poor team marking on another corner resulted in an open header.

“Tomorrow is our final, and everybody understands that,” captain Freddy Adu said Sunday on the USSF’s Web site. “We know what we have to do to move on. Guys look motivated.”

Added Porter: “There’s no doubt in my mind that we’re going to get the result.”

Join me on the blog sometime after 8 p.m. for the U.S. lineup, followed by match updates and commentary.