The United States set a 129-run target which the West Indies chased in just 10.5 overs which gave a massive boost to their net run-rate.
Earlier, the Windies won the toss and decided to bowl first against their opponents.
Batting first, the US were bowled out for 128 in 19.5 overs after a clinical bowling display by the home side.
Roston Chase was the pick of the bowlers with figures of 3-19 in four overs. Andre Russell also clinched 3-31 in 3.5 overs.
Opener Andries Gous top-scored for US with 29 runs in 16 balls. Nitish Kumar contributed 20 runs, while Ali Khan remained unbeaten on 14 runs in six balls.
Both teams lost in their respective opening Super 8 match which made this a virtual do-or-die contest.
Teams:
United States (Playing XI): Steven Taylor, Andries Gous(w), Nitish Kumar, Aaron Jones(c), Corey Anderson, Milind Kumar, Harmeet Singh, Shadley van Schalkwyk, Nosthush Kenjige, Ali Khan, Saurabh Netravalkar
West Indies (Playing XI): Johnson Charles, Shai Hope, Nicholas Pooran(w), Roston Chase, Rovman Powell(c), Sherfane Rutherford, Andre Russell, Akeal Hosein, Alzarri Joseph, Gudakesh Motie, Obed McCoy