18-year-old Weah, who was born in New York and opted to represent the country of his birth opened his international acount with the final goal of the game after 58 minutes as the US ran out comfortable winners.
The PSG youngster was one of a couple of potential future stars selected by caretaker boss Dave Strachan, with Werder Bremen's Josh Sargent (18) also getting on the scoresheet, scoring his side's second.
Weah has made three appearances for the PSG first team and made his international debut back in March when he came off the bench in a 1-0 win over Paraguay, becoming the first player born since the turn of the century to represent the US national team.
The pair were the leading lights in a youthful US side, with the starting line-up boasting an average age of 22 years and 160 days.