George top-scored again for Great Britain with 14 points
Great Britain will play hosts Turkey on Saturday for fifth place after losing 78-67 to Macedonia in their second game of the Efes Pilsen event in Ankara.
Chris Finch's team slipped 16 points down in the third quarter and he described his team as "embarrassing".
Nick George led GB's scoring with 14 points and Andrew Betts added 11.
"For the first time in our campaign I'm very disappointed with my team - I thought we showed no heart," coach Finch said after the game.
Flinder Boyd made yet another return from his recurrent ankle problem but Joel Freeland stayed back at the hotel with a stomach bug.
GB started brightly with a 9-0 run - all of it coming from the big men Betts and Robert Archibald - but Macedonia's immediate reply was a 10-0 tear and they led 23-17 at the end of the first quarter.
It was embarrassing.... I thought they played like spoilt kids
Great Britain coach
Macedonia had blazed 16 three-pointers in Thursday's easy win over Latvia and they hit four against GB in the first half, the last one capping a 10-0 run to give them a 39-27 half-time lead.
George, one of the successes of the summer, started the second half with five points in a 7-0 run that offered hope to GB.
That all but evaporated when Todor Gecevski, Riste Stefanov and Damjan Stojanowski all hit threes in a 13-2 run that gave the former Yugoslavs a 16-point advantage.
Trailing by 12 going into the fourth quarter, GB finally hit their first three-pointers of the game - a pair from Jarret Hart and another from George - as the final period threatened to become a shoot-out, Macedonia edging them with four successes.
A pair of free throws from Archibald reduced the lead to 10 points with 4:17 remaining in the game and a three from Mike Lenzly 33 seconds later brought the deficit into single figures.
Lenzly's next two efforts missed, however, and GB's hopes of an unlikely comeback win expired with them.
GB captain Andrew Sullivan admitted the defeat to Macedonia was, "Not one of our better efforts."
He added: "We've been playing well of late and all the guys are extremely disappointed with the effort we put out today. We know as group we can play better than this."
Finch sounded at the end of his tether after a seventh defeat in eight starts this summer for his patched up team, already missing Chicago Bulls star Luol Deng and last year's impact player, Pops Mensah-Bonsu.
"It was embarrassing, our teams always play hard, (but) tonight they didn't play hard, they didn't help each other out," he told BBC Sport.
"I thought they played like spoilt kids and they have no right to do so because we haven't accomplished anything yet.
"It's even harder because we've been trying to work with them and cater to some of their requests and this is the performance that we get.
"The British mentality is always one of a fighter. Tonight we didn't do that any honour."
The coach also looked ahead to Saturday's test against Turkey in a consolation game that will be the team's final outing before they travel to Warsaw for the start of next month's EuroBasket finals.
"I think it's a perfect test for us given our circumstances because I know they'll be pretty upset with the way that they've played over the last couple of days.".
"We know we have a good game of basketball in us and we're expecting a tough game and a good crowd. Hopefully we'll have a little more motivation tomorrow."