Melbourne City had a terrible record at Etihad but after a scintillating display, when they destroyed local rivals Melbourne Victory 4-1, they might want to play there every week. 

Call it the Cahill factor, call it the coming together of the City Football Group's vision for their Australian subsidiary, call it what you like. But it was dramatic, it was exciting, it was exhilarating. And hugely impressive.

It has been a lifetime of amazing achievement for Cahill and his A-League debut for his new club City simply continued the unbelievable narrative that has characterised his career.

But even he might not have imagined scoring in the way he did to put his new team on the road to a win that is a huge warning shot for the rest of the competition.

Sure, he would have visualised hitting the target, but scoring a "worldy"? Perhaps not even a man possessed of his self belief would have hoped for that much.

But that was how Cahill repaid the first instalment on the reported $3 million-a-year salary his new employers are shelling out for his services, striking with a wonderfully placed shot from some 40 metres out.

It was the icing on the cake of what was a tremendous first-half performance from City where they played some sparkling football and left Victory chasing shadows as their hosts failed to come to terms with City's slick passing, quick feet and energetic movement all over the pitch.

Cahill's strike came after Bruno Fornaroli won an aerial scramble against Victory centre back James Donachie just past the centre circle. As the ball fell to ground there looked to be nothing on.

But Cahill, who was aware that Victory keeper Lawrence Thomas was off his line, seized on the loose ball and, without breaking stride and barely glancing up, hit a wonderful looping drive over Thomas and into the back of the net.

For an instant the stadium, as if not quite appreciating what it was seeing, seemed to hold its breath before erupting, with joy from the City fans, and stunned sighs of incredulity from the deflated Victory supporters.

In truth Cahill had rarely threatened before his critical intervention, but it was obvious he was pumped and ready for action from the opening minute, as his heavy challenge on Alan Baro made clear. After Cahill clattered into the Spanish defender the Victory stopper had to leave the pitch to stem a cut under his eye.

Cahill then got himself involved in a push and shove with Victory's firebrand Fahid Ben Khalfallah after Jason Geria's foul on Fernando Brandan as Victory's frustration became apparent early on.

Bruce Kamau, the young City winger, was causing all sorts of problems every time he got on the ball, while Neil Kilkenny and Luke Brattan kept things locked down in central midfield.

City doubled their lead in the 31st minute through Fornaroli, the league's golden boot winner last year, who was striking for the first time this season.

After another neat build up that left Victory frazzled, City's Argentine Nicolas Colazo flighted a cross to the far post. Fornaroli escaped his marker and the Uruguayan was all alone as he stooped to head past an exposed Thomas.

Victory barely troubled City's stand in goalkeeper Dean Bouzanis, making his debut for the club in place of suspended No.1 Thomas Sorensen.

They were being forced so deep by City's possession and constant attacking that they struggled to find players in forward areas, and could have gone to the break three down but for Thomas's good save to deny Colazo's curling free kick at his far post.

City picked up where they left off after the interval and continued to drive on in search of a third goal. The sealer came just seven minutes after the restart and it was the excellent Kamau who was the provider. 

The winger looks spindly but his appearance belies his strength. He muscled Baro off the ball and as the Spaniard sprawled to the ground he hared off towards goal. Instead of blasting in a shot from a wide angle he kept cool, looked up and squared a pass to Brattan, who gleefully slammed the ball past Thomas.

Victory got some small consolation just after the hour mark when a wonderful solo run by New Zealand international Marco Rojas pulled a goal back.

But their relief was short lived, as City stretched their lead to three again shortly after. This time it was their other Argentine, Fernando Brandan, who did the damage. His body strength was too much for Geria as he chased down a through ball and once clear he fired past Thomas at his near post.

Last week in Sydney the sky blues 4-0 win over local rivals Western Sydney was described as a demolition derby, even though there were plenty of pundits who argued that the scoreline did not quite reflect the reality of that game.

No-one who watched this match could say that the scoreline did not tell the tale of the game. This was not a demolition derby but a derby humiliation. 

Victory is used to being the top dog in Melbourne. It's often folly to read too much into early season results. But Victory will need to improve a lot on this showing to be competitive with City the next time they meet.