Farhan's knock of 73 off 41 balls helped Pakistan post 9-190 in the group A clash, before spinners Usman Tariq and Shadab Khan took five wickets between them to ensure the US could not replicate their shock 2024 win over Pakistan despite a a defiant 50 from Shubham Ranjane.
Put in to bat first in Colombo on Tuesday, Farhan hit three boundaries against Ehsan Adil, the former Pakistan international debuting for the US, before hitting Milind Kumar for two sixes to get Pakistan to 0-54 after five overs.
But after Shadley van Schalkwyk dismissed Saim Ayub (19) and Pakistan captain Salman Ali Agha (1) in the sixth over, Babar Azam and Farhan cautiously consolidated their innings, adding 35 runs in the next five overs.
Babar picked up the pace in the 13th over, hitting his first two boundaries and a six as Harmeet Singh conceded 21 runs. But the former Pakistan captain fell to Mohammad Mohsin soon after for 46 as Kumar caught him at long on.
Player of the match Farhan's fighting knock, which included six boundaries and five sixes, came to an end in the 16th over as he got caught trying to hit Singh for a six.
But Shadab Khan kept the pace going, hitting a hat-trick of fours against Adil to add 28 runs in the next two overs, and scored a quick 30 off 12 balls before falling to Van Schalkwyk.
Van Schalkwyk, 37, ended his spell with 4-25, the same figures he enjoyed against India in Saturday's campaign-opening game.
Chasing 191, Shayan Jahangir got the US off to a bright start, with two fours against Shaheen Shah Afridi in the first over, and a six over the long-on boundary against Ayub in the next.
But Pakistan introduced spinners from the third over to control the flow of runs. After Nawaz dismissed Shayan's fellow opener Andries Gous (13) in the fifth over, the US added only 26 in the next five overs.
A frustrated Shayan was one run short of a half-century when he got caught trying to hit Shadab (2-26) over long on.
Kumar (29) tried to help Ranjane revive the chase with a 54-run partnership for the fourth wicket, and Ranjane (51 off 30 balls) hit Afridi for back-to-back sixes, but it was too little too late.
Tariq (3-27) allowed only three runs as he took two wickets in back-to-back deliveries in the 19th over, leaving the US 39 runs short of victory in the last over.
The US could only reach 8-158 as they suffered their second straight loss in the tournament.
