Great Britain coach Chris Finch admitted his team had taken some steps back in their preparations for the Olympics as individual mistakes contributed to a heavy 118-78 defeat against the United States.
Although they hung with the defending champions for most of the first quarter, American pressure told as British turnovers mounted and by the end the visitors were able to entertain the sell-out crowd in Manchester with some spectacular dunks.
Britain came into the game having recorded their first wins of the summer against Portugal in Sheffield, but against the best team in the world the game got away from them.
"It was a disappointing performance in the way the second half unfolded," Finch said.
"Compound mistakes hurt us, we'd have a turnover or a missed defensive assignment and it snowballed from there.
"But the biggest benefit for us of playing this game was to play a team of this calibre, it should case-harden us, and our guys will have learned from this process.
"We played well at times in the first half, but in the second half we never really got into the game."
Britain got the first points of the game when Joel Freeland made space inside, but it was the only lead of the game they would enjoy.
Britain at least stayed with the Americans, with back-to-back dunks from Pops Mensah-Bonsu making it 13-10 with 4:22 to go in the first.
Kyle Johnson's free throws got it back to 23-20 late in the first quarter, but the Americans responded with a 14-0 run as their pressure told.
Aside from that scoring run, Britain had managed to stay close to the Americans, who led 55-37 at half-time.
But early in the second half, Deron Williams hit three straight three-pointers to carry the United States 25 points clear.
Freeland, who has just signed for the Portland Trail Blazers, was given a 'welcome to the NBA' present from Tyson Chandler with a huge block, but recovered moments later with a nice move for two.
The 25-year-old admitted Britain had been a little overawed by the Americans.
"We had to be better prepared mentally," he said.
"We gave them way too much respect, me personally and the team collectively.
"We maybe came out a bit scared and worried about them all the time when we've got to worry about ourselves."
As the third quarter progressed, Williams kept the threes raining in and a big slam from James made it 75-46.
It was turning into a blow-out, and as the fourth quarter began, the Americans took their lead to the 40-point mark on a slam from Anthony Davis.
A three-pointer from James Harden took the Americans into triple figures before they took it in turn to score dunks in the closing minutes.
United States coach Mike Krzyzewski praised Britain's effort in the face of his own exceptional team.
"GB played really well," he said.
"Luol (Deng) is one of the better players in the world, and I like their toughness.
"We're much quicker than they are and that produced a lot of turnovers. We were very selfish in that regard, but I like the way they're coached. They've come a long way in the last few years."
Deng led Britain with 25 points while Mensah-Bonsu had 12 and nine rebounds, and Andrew Sullivan had 11 points, all in the final quarter.
Ogo Adegboye, the final cut from the Olympic squad, was also given some minutes as the 13th player, and made his mark with a late three.
Williams and Carmelo Anthony had 19 points each for the Americans, while LeBron James added 16.
The turnovers told a big part of the story, with the United States scoring 33 points from the 26 turnovers committed by Britain, while committing only nine themselves.
"We have to avoid turnovers," Finch added.
"We know teams are going to come and pressure us because we're a little young, a little green and a little small in the backcourt.
"We have to take care of the ball."