This was the last gold medal of the 2016 Rio on Sunday and the 25th Olympic victory of the US, which also had perfect 8-0 records in 2008 Beijing and 2012 London, Xinhua news agency reported.
This was the first Olympic medal for Serbia since 1996 Atlanta Games, when the then Yugoslavia won the silver medal after losing to the US.
The US beat Serbia 94-91 in the preliminary round, but proved it is a different story when the gold medal is on stake on Sunday.
An organised Serbian team produced enough trouble for the US, as they did in the previous encounter, when the lead was exchanged five times and the game was tied four times in the first quarter.
But solid defence of the Americans shattered the confidence of the Europeans, who were hammered on one-on-one situation. The US used a 24-7 run, initiated by Kevin Durant who scored 18 points in the second quarter, to take a comfortable lead on 43-22.
Serbia, which missed the 2008 and 2012 Games, never found their rhythem of typical team work as the game was more like an NBA one.
The US led 52-29 after two quarters, 79-43 after three before they won another one-sided game. The Americans averaged a 22.5-point winning margin in the tournament.
Durant had the game-high 30 points while DeMarcus Cousins had 13 points and 15 rebounds for the US.
The US beat Serbia on the board by 54-33 and led as many as 41 points.