The Boomers, featuring a core of experienced stars led by Patty Mills and Andrew Bogut, held their own in the first half on Thursday evening (August 22) before a third-quarter blitz from the Americans put the game in Melbourne beyond reach.
"We got good learnings from this game," Lemanis said as he fine-tunes preparations for the World Cup in China, which starts on August 31.
"There's time to get this where it needs to be and what we do have is a core of guys who have played together in big events for a period of time so that helps expedite the growth."
Australia have never won a medal at the World Cup but some pundits are tipping this to be their year, given their roster of talent.
Along with Mills, Utah Jazz's Joe Ingles, the Cleveland Cavaliers' Matthew Dellavedova, Phoenix Suns centre Aron Baynes and Lithuanian-based Jock Landale all started on Thursday (August 22).
But it was National Basketball League shooting guard Chris Goulding who impressed most off the bench, leading Australia with 19 points alongside Mills.
Lemanis said defence was a key area to work on ahead of a second clash with the United States on Saturday (August 24).
"As a group, the first place we want to hang our hat is defensively and there were some periods in that game where we weren't where we wanted to be at the defensive end," he said.
"First half, perhaps some of that generated from the stuff we got offensively but then (we) did a nice job of sort of just settling it down, got back into the game, got into it defensively and then ground our offence to get some looks we wanted.
"Obviously that third quarter, the bite went out of our defence a little bit," he added.
"Some stuff we executed all right and other stuff there were some breakdowns, that I think we can fix, that led to them to making some shots and feeling pretty good about life."