Pouriya Hossein Khanzadeh collected 22 points for Team Melli, while Torey Defalco scored 32 points for the US, Tehran Times newspaper reported.
This was Iran’s first win out of nine matches in the 2024 VNL.
Iran are scheduled to play the Netherlands on Thursday.
The VNL Preliminary Phase features three competition weeks per gender, with each of the 16 teams playing 12 matches.
The seven best-ranked national teams in the Preliminary Phase will join hosts Poland for the Finals, which will be held in Lodz from June 27 to 30.