The Swans never recovered from a slow start and trailed from the outset on their way to a 15.10.(100) to 9.13.(67) loss.
The visitors travlled north on the back of a five-year unbeaten run against the Queensland team, but were out-tackled by a more desperate Lions outfit whose pressure told heavily in the all-important midfield battle.
The Swans chances were flattened by an injury to gun midfielder Jared Crouch, who twinged his left hamstring early in the second quarter.
His departure allowed Travis Johnstone to cut loose and a host of his teammates followed suit.
The Swans had their chances in the second half but inaccurate kicking proved costly, with Darren Jolly, Jude Bolton, Martin Mattner and Jarred Moore all missing gettable shots.
The Lions were not faultless in that regard but through Jonathan Brown and Daniel Bradshaw (four goals each), and the dangerous Justin Sherman (three), had more avenues to goal.
The Swans renowned close checking failed to materialise from the opening bounce, allowing the Lions to establish a 20-point quarter time lead that the visitors were never able to peg back.
Jude Bolton was a standout with eleven touches in the first term and he was ably supported by the likes of Jarrad McVeigh, Rhyce Shaw and Kieran Jack.
But the Lions were winning the hard ball and applying intense tackling pressure to stop the Swans run off the half-back line.
Barry Hall lifted his side with a goal from the boundary line in the second quarter before second-gamer Brett Meredith, 20, added more inspiration with a booming 60m set shot on goal.
But that would be as close as the Swans got. The Lions kicked the next five in a row, setting up a 37-point buffer at the major break and effectively ending the contest.
Craig Bolton did a solid job on Daniel Bradshaw but was dragged deep into the goal square, limiting his ability to rebound from defence.
Dual Brownlow Medallist Adam Goodes was worn tightly by Joel Patfull and had limited influence on a fixture he has made his own in previous seasons.
Darren Jolly switched up forward late in the third quarter and kicked two goals.
The Swans must now face up to Carlton at the SCG next Saturday while the Lions have a six day break before taking on Collingwood at the Gabba next Friday night.
Brisbane Lions 4.4 10.6 12.9 15.10 (100)
Sydney Swans 1.2 4.5 7.10 9.13 (67)
GOALS
Brisbane Lions: Brown 4, Bradshaw 4, Sherman 3, Rich, Drummond, Notting , Adcock.
Sydney Swans: Hall 3, Jolly 2, White, Meredith, Barlow, Moore.
BEST
Brisbane Lions: Patfull, Drummond, Brown, Selwood, Adcock, Macdonald
Sydney Swans: Bolton, Bevan, Shaw, Jack, Jolly, Hall
INJURIES
Brisbane Lions: Nil
Sydney Swans: Crouch (hamstring)
Reports: Nil
Umpires: H.Ryan, S.Meredith, S.McInerney
Crowd: 24, 984 at the Gabba
The views expressed in this article are not necessarily those of the clubs or the AFL
