Nikola Jokic has had the last laugh as Serbia came from 24 points down to beat the Boomers 95-90 in overtime and book an Olympic semi-final.
In his last Games outing, Patty Mills was immense as Australia burst out of the blocks, the five-time Olympian then hitting a clutch bucket to take their Paris quarter-final to overtime.
But, down three, the reigning NBA MVP took control with two stops and two buckets to have the final say on Monday.
He finished with 21 points, 14 rebounds and eight assists against Tokyo's bronze medallists, Serbia scoring the game's final eight points.
Mills (26 points) went berserk either side of quarter time in a 20-point Australian run that put them 22 clear.
Coach Brian Goorjian said it was the best basketball he'd seen from an Australian side in any of his four Olympic campaigns.
"But when it came to the nut-crunching time, turnovers were our issue in the whole tournament," he said.
The next World Cup is in 2027 and Mills will turn 36 on Sunday.
Along with fellow five-time Olympian Joe Ingles (37 in October) and Matthew Dellavedova (33) it was likely Mills' final fling in a side destined to be led by 21-year-old point guard Josh Giddey (25 points, five rebounds, four assists).
"We've just enjoyed every moment of this journey," said Mills, who steered the Boomers to a breakthrough Tokyo bronze three years ago.
"It hasn't been a smooth-sailing ship, but you do it together and you never take those moments for granted.
"But through the thick and thin and ups and downs, happy tears, sad tears, it's been an incredible journey to be able to share with those guys."
Jokic finished with 21 points, 14 rebounds and eight assists, Serbia scoring the game's final eight points just as Australia had shot to a three-point overtime lead.