For much of the game, the American's pace and athleticism was too much for the British team who struggled under pressure.
As the quarter came to a close, GB's inability to keep possession was ruthlessly punished by the US. An impressive alley-oop from Russell Westbrook, on his way to 15 points on the night, helped put his team 33-20 up at the whistle.
GB basketballers ready for Olympic test
The game continued in similar vein with the 13-time Olympic gold medallists capitalising on GB's high turnover rate - 14 by half-time.
The US were fast and decisive in their play with crowd-favourite Kobe Bryant enjoying much success in the paint as Britain struggled to contain the US's attack.
Trailing 55-37 at the interval, the hosts came out in the third with renewed energy, but it was quickly thwarted as Lebron James, who posted 16 points on the scoreboard, slammed a ferocious dunk mid-way through the period to extend his side's lead to 75-46.
It was then plain sailing for the American's as players lined up to post dunk after dunk, much to the delight of the Manchester crowd.
Deng, who earns his living with NBA side Chicago Bulls, said: "They're the best team we've seen.
"Some of their guys are the best competition we've played against. For 40 minutes they're very hard to keep in check.
"Physically you've got to be in top shape. We believe in each other, we've still got work to do.
"We'll take one game at a time. It's going to take a lot of effort and a lot of work but we've got to watch this game and learn from it."
US guard Williams, who was part of the 2008 Olympic team that won gold, added: "It was a great game for us.
"We're using these warm ups to find some rhythm and find some chemistry. We're learning about our team.
"It was a good win for us tonight against a tough Great Britain team."
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