Trinidad and Tobago qualified for the final CONCACAF World Cup qualifying round on Friday after a 2-2 draw with Guatemala, and the United States will almost certainly join them after demolishing St Vincent and the Grenadines 6-0.
Teenage substitute Christian Pulisic scored a second-half double in the U.S. rout that took them to 10 points in Group 3 with one game left.
Trinidad and Tobago top the group with 11 points and Guatemala have seven. The United States' goal difference is 12 better than Guatemala's meaning they are virtually certain of advancing.
St. Vincent and the Grenadines are bottom of the group with no points.
Three first-half goals put the United States in charge against a plucky team from the small Caribbean island nation of barely 100,000 people.
Bobby Wood opened the scoring in the 28th minute when he curled a shot into the far corner from just outside the box at the Arnos Vale cricket ground in Kingstown. Matt Besler's strike and a Jozy Altidore penalty extended the lead before halftime.
St. Vincent had the ball in the net twice early in the second half, but the goals were ruled offside.
Seventeen-year-old Pulisic then showed his class after coming off the bench.
The Borussia Dortmund striker scored his first goal after collecting a pass with a deft touch inside the box and completed the win in stoppage time when he was given too much time just outside the box and placed the ball clinically inside the post.
Sacha Kljestan also scored for the United States. "It's a nice win and the team deserves a compliment," coach Jurgen Klinsmann said, "but we've gotta finish it off Tuesday versus T&T."
The first two teams in each of the three groups qualify for a round robin competition, from which the top three qualify automatically for Russia and the fourth-placed side goes into an intercontinental play-off with a team from Asia.
Trinidad and Tobago progressed but made heavy going of their home tie against Guatemala. The visitors took the lead through Carlos Ruiz in 36 minutes, but Joevin Jones scored in the 45th and 62nd minutes to put the home side ahead.
Guatemala's Cristian Jimenez was sent off six minutes from the end but Ruiz headed home an equaliser two minutes later to keep alive their slender hopes of reaching their first World Cup Finals.
In Group 1, Canada's hopes of progressing were hit hard by a 2-1 loss to Honduras. James Manjrekar headed Canada into the lead in the 35th minute but Mario Martinez drew the sides level on the stroke of half time and Romell Quioto got the winner five minutes into the second period.
Honduras are now in pole position to qualify from Group 1 behind Mexico, the only team so far to have cemented their place in the final six. Mexico play El Salvador later on Friday.
(Reporting by Andrew Both in Cary, North Carolina and Andrew Downie in Sao Paulo; Editing by Ken Ferris/Peter Rutherford)