The Lions' 10.19 (79) to 6.9 (45) Sunday night victory came with just two men on the bench for almost three quarters after likely anterior cruciate ligament tears for Lincoln McCarthy and Darcy Gardiner.
Brandon Starcevich (calf) was injured in the warm-up while Noah Answerth (concussion) was another early loss.
That propelled teenaged emergency Logan Morris into a debut on 10 minutes' notice, just hours after playing a full game in the Lions' VFL team and polished off an afternoon McDonald's meal.
Victory was the Lions' first from four games at home this season, crucially improving them to 3-5 and taking the wind out of the Suns' (4-4) sails.
"I've been involved in footy for a long time and never seen anything like the carnage that happened," coach Fagan said.
"It was the most amazing and courageous win I've ever seen, by any group of players I've had anything to do with.
"It shows a great deal of character and will go down in our club as one of our greatest ever wins."
If Gardiner and McCarthy's injuries are ACL tears - Fagan said "they more than likely are" but that scans on Tuesday will confirm - it would bring to five the number of Lions currently sidelined by the injury.
Will Ashcroft, Keidean Coleman and Tom Doedee are all in various stages of ACL rehabilitation while Zac Bailey (ankle) and Cal Ah Chee (hamstring) are also sidelined.
Jed Walter missed the mark and concussed Noah Answerth as Brisbane's injury toll mounted.
All that commotion didn't stop the Lions' first-half clinic, with Dayne Zorko (career-high 39 disposals, including 35 kicks) engineering the performance from half-back.
Zorko's prolific and accurate service sliced the Suns up through the corridor to earn him his first Marcus Ashcroft Medal.
Matt Rowell (16 disposals, two clearances) was quietened by Josh Dunkley as the Suns lacked forward thrust.
Brisbane led by 40 point at halftime with Zorko and Lachie Neale (34 disposals) leading the way.
Oscar McInernery's return from concussion was influential, keeping a lid on Suns rival Jarrod Witts, while Hugh McCluggage (31 touches) was also damaging.
Oscar McInerney tackles Matt Rowell early on in the Lions ruckman's welcome return from concussion.
Not even 10 consecutive Lions behinds, and some complete misses, could bring the Suns back into it as the visitors squandered some golden opportunities of their own.
Suns coach Damien Hardwick said his men were unable to cope with the early heat of a Lions' side that was performing better than their 2-5 record suggested.
"We got jumped," he said.
"That and ... they've been under the pump this week.
"Indicators are pretty prevalent in how a side's going, and their indicators are very good.
"Some sides are winning at the moment that long term are probably not going to win."
Bruce Reville made his Lions debut in more traditional circumstances than Morris and was a clear favourite of the 30,285-strong crowd that was almost 3,000 greater than any other derby figure.
Jack Payne contributed to a strong defensive effort by the Lions.
The 18-year-old Morris wearing a pair of undersized teammate's boots after he forgot to bring his to the ground, capped a whirlwind day with a second-quarter goal.Â
But he could have had a swag if not for two set-shot misses and another snap that sailed just wide.
His was the Lions' last before Charlie Cameron walked into an open goal and ended a run of 10-straight behinds late in the final quarter.
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