Despite entering Saturday's Preliminary Final against Central Coast Mariners as underdogs, Glory managed to hold their opponents to a 1-1 draw after extra-time, before emerging victorious 5-3 on penalties.
And while they have been thumped twice by Roar earlier this season, Ferguson's charges will take heart from the 3-3 draw they recorded at the nib Stadium back in January..
"They are one-off games and anybody can beat anybody in the finals," Ferguson said, according to the West Australian.
"We're going to go there with the attitude and confidence that we can beat them."
The draw with Roar back in January was also the result that gave Ferguson, who was then under severe pressure, breathing room, allowing him to mastermind Perth's subsequent revival.
"It's funny how football works," the 45-year-old Scot remarked. "At Christmas time, you're hanging on to your job and you're hoping to get a chance to keep it going.
"[Chairman] Tony [Sage] and the board showed great faith in keeping me on and I'm absolutely delighted that we've reached the final because it pays back the faith Tony has shown."
While Glory spent large parts of the match of the back foot, with goalkeeper Danny Vukovic putting in an inspired showing, Ferguson does not believe good fortune was the main reason they managed to beat the Mariners.
"I suppose you could say that at times we did ride our luck but then Smeltzy [Shane Smeltz] has missed an absolutely fantastic chance at the end," the former Rangers midfielder added.
"He could've clinched if for us there as well."
Brisbane booked their place in the Grand Final after beating Central Coast 5-2 on aggregate in the semi-finals.