In a battle of teams tipped to fight for the wooden spoon, the GIANTS poured in five supergoals in the second term alone and seven overall to turn a one-point quarter-time deficit into a remarkable 58-point lead at the main break.
From there it was all GWS, with All Australian Jeremy Cameron kicking four goals and one supergoal in a 7.11.10 (139) to 0.10.11 (71) annihilation of a terribly disappointing St Kilda outfit.
Dylan Shiel kicked three supergoals of his own, while Tomas Bugg, Adam Treloar, Curtly Hampton and Rhys Palmer all stood out for a GIANTS side that had winners all over the ground.
With Josh Hunt, Heath Shaw, Shane Mumford and Dylan Addison providing some welcome balance to their young list, the GIANTS look a far more dangerous prospect heading into 2014.
Both sides were fielding relatively strong line-ups and the result leaves new Saints coach Alan Richardson with plenty of work to do before the season gets underway.
Nick Riewoldt kicked two first-quarter goals and Jarryn Geary and Jimmy Webster had their moments, but it was otherwise a poor showing from the Saints, who face Port Adelaide in their final hitout next weekend.
An apparent hamstring injury to Lenny Hayes only added further injury to insult for a St Kilda side already missing best and fairest winner Jack Steven for the next two months with a broken foot.
In a town that produced footballing royalty in Wayne Carey and Paul Kelly, it was modern day heroes Riewoldt and Cameron who got their respective sides underway in the first quarter.
Riewoldt got the opening goal on the board in the second minute of the game courtesy of a free kick against GWS co-captain Phil Davis, a scenario that would repeat itself at the end of the term.
Cameron also kicked two goals in the first quarter, getting the better of a tight duel with James Gwilt, as the GIANTS took a one-point lead into the first break.
While the first term was an arm wrestle, the second was an absolute avalanche, starting with a supergoal and a goal from a fresh looking Jonathon Patton.
Nick Haynes, Dylan Shiel, Will Hoskin-Elliott and Cameron all got in on the supergoal action as GWS tore the game wide open.
The GIANTS missed some opportunities in the third quarter, but still managed to stretch the lead to 68 points before romping home in the final term.
WHAT WE LEARNED
It was only a trial match, but the signs were clear that the GIANTS should take a significant step forward this coming season. The mature-aged additions have filled some holes and the glut of young talent is making the necessary improvements.
NEW FACES
For a 19-year-old playing his first senior game, Josh Kelly was far from overawed and showed some good hands and a calm approach. Jed Lamb was dangerous around the half-forward line, while Dylan Addison spent time at either ends of the ground.
GWS 0.4.3 5.7.5 5.10.6 7.11.10 (139)
ST KILDA 0.4.2 0.5.4 0.6.7 0.10.11 (71)
SUPERGOALS
Greater Western Sydney: Shiel 3, Patton, Haynes, Hoskin-Elliott, Cameron
St Kilda: Nil
GOALS
Greater Western Sydney: Cameron 4, Addison, Smith, Patton, Bugg, Lamb, Palmer, Frost
St Kilda: Riewoldt 2, Lee 2, Weller, Geary, Saunders, Dunstan, Curren, Montagna
BEST
Greater Western Sydney: Bugg, Cameron, Treloar, Palmer, Shiel, Haynes, Hampton, Kennedy
St Kilda: Riewoldt, Geary, Webster, Montagna
INJURIES
Greater Western Sydney: Coniglio (concussion)
St Kilda: Hayes (hamstring)
SUBSTITUTES
Greater Western Sydney: Townsend replaced Coniglio at quarter time; Plowman replaced Mumford in the final term.
St Kilda: Schneider replaced Billings at quarter-time; Ross replaced Delaney in the second term; Delaney replaced Gwilt in the third term.
Reports: Townsend reported for high contact on Armitage in the fourth quarter.
Umpires: Stevic, Jeffery, Lehner, Pawley
Official crowd: 7,944 at Robertson Oval