However the USA hit back to score 21 consecutive points and although Britain produced another flurry in the third period, their hopes of a famous victory slipped away.
"This is a good outcome for us," said GB captain Jo Leedham, who scored a game-high 21 points and contributed four assists. "I don't think we executed great but we showed ourselves that when we are executing, we can play at that level.
"We should have the belief and confidence that we can play with these players. Their athleticism is crazy. They're the most athletic team I'm ever going to face. When you put all 12 of those players together, it's amazing. But we have to do the little things - the grit, the aggression - that allows us to compete with teams like that."
Julie Page recorded six points along with her eight rebounds, as Azania Stewart added nine points and three rebounds, and Temi Fagbenle contributed four points, five rebounds and two assists.
Watched by both the Standard Life GB men's squad, and their USA counterparts, ahead of their clash in Manchester on Thursday, Maher's team picked up where they had left off against France three days earlier with an astonishing start that put the world champions under immediate pressure.
Stewart delivered back to back baskets to open up a 13-8 cushion and then Jenaya Wade-Fray's first touch off the bench extended the gap.
Leedham turned up the heat further with consecutive scores and with 2:58 left in the first quarter, GB's advantage was an impressive 21-10.
Inevitably, the USA eventually hit top gear and accelerated, with Atlanta Dream guard Angel McCoughtry sparking a 21-0 run.
Another 10-0 flurry widened the deficit and with Maya Moore scoring 15 of her team-best 18 points in the first half, her team held sway with a 47-32 lead at the interval.
Creditably, Britain did not roll over. Instead, they fought back. A 12-4 start to the third period raised the prospect of a comeback and USA head coach Geno Auriemma was forced to call a time-out when Stef Collins - who added 14 points and four assists - hit a three which tightened the difference to seven with 4:51 left in the third period.
Just 54-47 in front, the USA again responded and this time, there was no stopping them.
Lindsay Whalen fuelled a 19-4 burst inside the next five minutes, and as the barrage continued into the fourth, the Americans lead peaked at 82-53 with six minutes left.
Maher, for one, saw ample positives: "We've come so far and I couldn't be prouder of the team. God willing everyone stays healthy, I think the country will be proud of their team. We're a contender and a participator in the A grade," said the GB coach, who will now prepare for his fifth Olympic appearance.
"Our players will look back on this as a milestone in their careers, hopefully. What a fantastic dress rehearsal for the Olympics," Maher added.
Collins was happy with how GB played, but felt that turnovers played a part in the loss.
"This was an amazing opportunity to play the USA, they are the number one team in the world and they came in with a lot of fire power, more power and more athleticism so it was good that we matched up with them most of the time," Collins said.
"They got aggressive, trapping us offensively and that hurt us, forcing us to turn the ball over but it was good to stay competitive in parts and we can be happy with how we attacked the game."
Maya Moore had a team-best 18 points and seven rebounds for the USA and backed Maher's claim that Britain is now a respected international side.
"We expected that from them," she said. "I wasn't surprised. Hats off to them, they came out to do what they were supposed to do."
The result leaves GB Women with a record eight wins and eight losses from their 16 build-up games for the Olympics.
The Standard Life GB men face the USA men tomorrow at the MEN Arena, tip-off 19:10.
