The reigning premiers reeled off the first four goals on Friday and never looked back, cruising to a 14.8 (92) to 6.15 (51) win to leapfrog Geelong into second place on the ladder.
In claiming Brisbane's first win in Geelong since 2003, Fagan ticked off the last "hoodoo'' broken under his tenure, which previously included losing streaks at the MCG and against Richmond and Sydney.
"It was good. When I spoke yesterday, I wasn't all that confident that we could tick it off because it's hard to come down here and beat the Cats," Fagan said.
"They've been an amazing team for a long time. Beating them at home is a pretty special thing to do.
"So we're really rapt as a football club, really happy with the contribution we got from all the players tonight. I thought it was a great team effort.
"We wanted to come here with a positive mindset. I don't think you can achieve much without it, particularly in these sort of environments.
"It was a bit of the approach that we probably had towards the end of the year last year. We just reignited it in a different way this week and the boys embraced it and we were able to get the result."
Brisbane snapped a two-game losing run and ended Geelong's five-game winning run in the process.
Geelong gave away free white T-shirts to the entire crowd of 35,367 fans to produce a "white-out" effect, ramping up the atmosphere for when captain Dangerfield led Geelong's players out.
But the Lions defied the build-up and exploded out of the blocks to silence the crowd and kick off a milestone game to forget for Dangerfield and 100-gamer Tyson Stengle.
Brisbane were as ruthless as Geelong were poor, picking off the Cats' errors and slicing them up at will.
Young key forward Logan Morris kicked five goals, while Cam Rayner (three goals) was dynamic as ever.
"He was huge, wasn't he?" Fagan said of Rayner.
Harris Andrews dominated Shannon Neale, while Dangerfield was blanketed by Brandon Starcevich.
With Lachie Neale well held by Tom Atkins, midfielders Hugh McCluggage (22 disposals), Josh Dunkley (30 disposals), Will Ashcroft (28 disposals) and Jarrod Berry (26 disposals) were excellent.
With Lions defender Darcy Gardiner a late withdrawal, Jeremy Cameron kicked four goals, while defenders Jack Henry and Tom Stewart worked hard.
Of Brisbane's first three goalkickers, Levi Ashcroft, Kai Lohmann and Darcy Wilmot, not one was born the last time the Lions won in Geelong.
The Lions took a 24-point lead into half-time but Geelong's hopes were flattened when Rayner kicked off another run of four unanswered goals at the start of the third term.
Geelong trailed by 32 points at the final change, but a minute into the fourth quarter Rayner smacked home his third to seal the Cats' nightmare.
"We played a really good team that was sharp tonight, and we were the opposite," Cats coach Chris Scott said, adamant the occasion hadn't played into things.
"If that's a pattern throughout your games, then you've got a problem, and you may not be a very good team, but I don't think that's the case with us. It hasn't been a pattern.
"it was a bad game to have an off night, because sometimes you can have a bit of an off night and get away with it but you can't against the quality of that opposition.
"I didn't think it was a complete disaster."
Both teams now have the bye, before Geelong return to action against Richmond on July 5 and Brisbane host Port Adelaide the same night.
