A healthy crowd of 22,970 was on hand at Suncorp Stadium and they got what they came to see - not just a Brisbane win, but a few glimpses of magic from the visiting 'Il Pinturicchio'.
Still nursing a hamstring strain, Del Piero tried his hardest to haul the Sky Blues back into a game they began on the back foot.
His two goals either side of half-time oozed class, but Sydney's porous defence saw the wind blown out of their sails after each one.
There was no denying the Roar, who released the pressure valve on rookie coach Rado Vidosic with a comprehensive and convincing performance.
Thomas Broich opened the scoring with Brisbane's first on the half-hour mark - although he didn't mean to.
From a free-kick 35 yards out, he floated a cross into a crowded penalty box that evaded everyone - including Ivan Necevski, who watched on with horror as the ball bounced past him harmlessly.
Three minutes later, the Sydney goalkeeper redeemed himself with a reflex save that denied Erik Paartalu, who latched onto a brilliant Broich cross from the left.
But the scraps fell into the lap of the towering Roar midfielder and with his second attempt, he made it 2-0.
Enter Del Piero.
Picked out in the final third by fellow marquee signing Brett Emerton, the Italian star was left far too much time and space by Jack Hingert, who chose to hang back and cut off the passing option to Ali Abbas instead of closing him down.
With a thundering left-foot shot from well outside the box, Del Piero taught the young fullback a lesson in marking he won't soon forget.
It was an incredible strike and at 2-1, it seemed to be a moment the Sky Blues could rally around in their first game under caretaker coach Steve Corica.
But on the stroke of half-time, Brisbane stretched their lead to 3-1 through Ben Halloran, who turned a spilled ball into his first goal in Roar colours with a classy, bending finish from the left.
Sydney struck back four minutes after the interval thanks to a second piece of Del Piero brilliance.
The 38-year-old beat Erik Paartalu before combining for the perfect one-two with Yairo Yau, which left him through on goal at the edge of the area and with only Michael Theo to beat.
And beat him he did - the former Juventus captain toyed with the Roar keeper, hesitating to pull the trigger just long enough to leave a stunned Theo flailing on the ground.
With an open net ahead of him, Del Piero completed his first-ever brace for Sydney with aplomb.
But he was perhaps upstaged by Besart Berisha, who put the home side up 4-2 on 57 minutes.
The Albanian - who idolised Del Piero as a child - strolled past four hapless Sky Blues defenders and then bagged his fourth goal of the season to complete the rout.
The win sees Brisbane jump off the bottom of the table and over Sydney, who remain on six points after conceding a whopping 14 goals in the past three games.