Hugh McCluggage kicked the match-winner from tight on the boundary inside the final two minutes as the hosts came from 24 points down to win 11.20 (86) to 11.15 (81) on Friday night.
A fourth-straight victory after a 2-5 start to the season shot the Lions (8-6-1) into the top eight for the first time - in fifth position ahead of games against 15th and 16th-placed sides Adelaide and West Coast.
The Demons' (8-7) fifth loss in seven games will be tough to swallow, Simon Goodwin's side unable to kick a final-quarter goal for a second-straight week.
Hugh McCluggage was a hero for the Lions, with his late goal giving them their winning lead. (Darren England/AAP PHOTOS)
Brisbane led by 15 points at quarter time but, powered by ruckman Max Gawn, midfielder Clayton Oliver (29 disposals, one goal) and five-goal forward Kysaiah Pickett, the Demons kicked six consecutive majors.
Pickett had four goals before halftime, but his fifth was the highlight, intercepting, fending, swivelling and then snapping off his non-preferred left foot as Melbourne flexed their muscles.
It was arguably the Demons' best football of the season as they dominated through the middle, with forward Bailey Fritsch negating the impact of Harris Andrews for good measure.
But the Lions turned the tables in the second half, inching back within 10 points in the third quarter and eventually cracking the Demons in the final 10 minutes of the match.
Lions coach Chris Fagan revealed he had posted McCluggage, Lachie Neale and Josh Dunkley's statistics on the whiteboard, alongside their opponents, at halftime and urged them to lift.
McCluggage had 21 of his 28 touches in the second half while Dunkley made 10 tackles and collected a game-high 32 disposals and Neale (six clearances, 29 disposals) matched Oliver's numbers.
"They found a way in the second half and ended up being our best players," he said.
"I very rarely do it ... but tonight I thought it was necessary and I know those blokes do respond when you do that to them."
They did their best to throw it away, with Eric Hipwood's heavy handball and Joe Daniher's hesitancy when teammates were open in front of goal undoing two certain majors.
"It was a rollercoaster ride ... so many opportunities and some great ones we butchered. But the good thing is we found a way," Fagan said.
Despite this mishap, Kai Lohmann was a key contributor for the Lions with a late goal. (Darren England/AAP PHOTOS)
Jarrod Berry and Kai Lohmann, with a neat left-foot snap, got the Lions to within a point before the returning Will Ashcroft's (18 disposals) hurried effort just missed to level the scores.
Demon Alex Neal-Bullen was then penalised for deliberately taking the ball out of bounds, and McCluggage threaded the needle from the boundary to give his men the lead.
Fritsch then snapped a behind and Melbourne went forward again, but Charlie Cameron scrapped for a loose ball, handballed to himself and ran it out of danger with inspirational zeal to secure the win.
Demons coach Simon Goodwin lavished praised on Pickett and Oliver and said Neal-Bullen's free kick was "not the reason we lost the game".
"A lot of people didn't give us a chance," he said. "I'm proud of how the boys performed but incredibly disappointed with the result. It was a game there for the taking and we walk away losing."
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