The US won the quarter-final 119-86 but Australia had shown some fight, opening the second half with 11 points to nil to pull within three points.
Mills ended a fine tournament with 26, including four three-pointers, and drew praise from US coach Mike Krzyewski and NBA superstar Kobe Bryant.
“Patty Mills just seems to get better and better," said Bryant, who blew the game open for the Americans with 20 points in the second half.
"Every time we face them and every time I see him, he seems to improve."
Krzyewski said Mills had been one of the competition’s outstanding players.
Mills this morning tweeted: “Couldn't be more proud of our boys. Such an awesome bunch of guys”.
World Champion BMX racer Sam Willoughby qualified sixth fastest after the seeding run of the men's competition in London last night.
The Crows Ambassador finished his run in 38.496 seconds to just miss a top four spot heading into tonight’s next stage.
