The Demons trailed by 24 points in the first half as the Lions flashed some of their brilliant best.
But it fell apart for the reigning premiers, with a 4.7 to 1.1 final term reflective of how the game turned.
The result follows the Lions' (7-2-1) lacklustre draw against strugglers North Melbourne last week and adds fuel to the under-pressure Demons' season as they improved to 4-6.
Clayton Oliver (23 disposals, seven clearances, one goal) surged back into form, using his tagging role on Lachie Neale (30 disposals) to build confidence and have an impact in attack.
Max Gawn bossed the ruck against Darcy Fort, winning hit-outs 54-17, after Oscar McInerney was a late out for the Lions.
Darcy Gardiner had shaped as the unlikely match-winner for Brisbane, the remodelled forward kicking a career-high four goals after managing just nine in his previous 168 AFL games.
Logan Morris kicked three and was among the many Lions looking sharp in the first half as they threatened to blow the game open.
But Jake Melksham (three goals) was impressive in his duel with Harris Andrews at the other end and the Lions kept turning the ball over - invitations the Demons eventually accepted.
The Lions led by 14 points at the final break but lost their run as the Demons moved the ball freely and could have won by more with straighter kicking.
Keidean Coleman had early impact in his first game for 14 months, his first touch a laser-like kick that surged the Lions forward and led to a Jaspa Fletcher goal.
Morris and Charlie Cameron provided sharp assists for teammates, with Morris rewarded later in the quarter with two quick goals of his own.
Eric Hipwood swung onto his left and booted a goal from beyond the arc and when Gardiner marked and goaled in the square the margin was out to four majors.
Noah Answerth's unforced error gave the Demons a look though. Melksham's second goal was the result and sparked a mini-revival as the Lions committed a series of uncharacteristic mistakes.
With Gawn's influence growing the Demons relished the stoppages, with Trent Rivers sneaking along the boundary line after a ball-up to make it a 13-point game at the main break.
Morris and Gardiner added to their hauls, with Gardiner even setting up Zac Bailey through a sublime drop punt at full pace.
But Oliver helped swing momentum, his desperation allowing Pickett an easy goal before the midfielder snatched possession and snapped a rare goal of his own.
3°C