The minor Premiers extended their brilliant unbeaten streak to 25 games thanks to first-half goals from Kosta Barbarouses and Erik Paartalu - the latter an absolute cracker - before Henrique grabbed a third midway through the second half to ensure the win before Thomas Broich capped it off with a late nail in the coffin.
It was their first triumph over Gold Coast in six games, inflicting a second consecutive defeat on the fourth-placed United ahead of the finals where they will take on Melbourne Victory at home whilst the Roar meet Central Coast Mariners in a two-legged semi-final.
GOAL Brisbane's Premier's Plate unveiling started perfectly when Kosta Barbarouses ended a six-match scoring drought when he received at the top of the area, turned to the right and curled into the top right corner in just the third minute.
Barbarouses almost had a second six minutes later when Erik Paartalu played a lovely ball into the path of the New Zealander but he put his shot wide of the mark before Glen Moss came to the rescue in the 11th minute when Henrique's shot was knocked away by the gloveman who backed his first save with another from Thomas Broich's follow-up.
Barbarouses was well up for the contest and fizzed a ball past Moss just before the half-hour mark about nine minutes before Ivan Franjic hammered goalward only to see the Gold Coast keeper produce a stellar save.
GOAL For all Brisbane's domination they managed to double their advantage in quite spectacular fashion when Broich advanced down the left before playing a ball for Paartalu who volleyed home into the top right corner in what is surely a goal of the year contender.
Gold Coast had been thoroughly outplayed in the opening 45 minutes but had the first chance of the second half through Shane Smeltz who forced Michael Theoklitos to tip over the crossbar with a free-kick before Anderson hit a sweet volley which the Roar custodian again kept out.
GOAL Brisbane were continuing to come strongly and got a third in the 65th minute when Franjic went to play a one-two with Henrique but the Brazilian had enough room to sum up his options and decided to lash it past Moss in the 65th minute, essentially wrapping up proceedings.
The home side still kept coming as Gold Coast struggled to create too much in the front third, prompting Ange Postecoglou to bring off Theoklitos in the 80th minute to give back-up keeper Andrew Redmayne his first minutes of the season.
GOAL The Championship favourites then managed to get a fourth when Barbarouses found skipper Matt McKay by himself on the left side of the area and the Socceroos midfielder was completely unselfish in cutting back for an unmarked Broich who rammed it home unchallenged from close range to send his side into the playoffs with a bang.
BR Michael Theoklitos (gk) (Redmayne 80'), Ivan Franjic, Matt Smith, Shane Stefanutto, Milan Susak, Erik Paartalu, Mitch Nichols (Visconte 59'), Matt McKay, Thomas Broich, Henrique (Bush 68'), Kosta Barbarouses
Subs - Andrew Redmayne (gk) (80'), Rocky Visconte (59'), Chris Bush (68'), Matt Mundy
GCU Glen Moss (gk), Steve Pantelidis, Dino Djulbic, Kristian Rees (Fitzsimmons 74'), Adama Traore, Michael Thwaite, Zenon Caravella, Anderson, Peter Perchtold (Harold 70'), Tahj Minniecon (Lustica 78'), Shane Smeltz