It sounds blasphemous to even suggest it, but Sydney FC may just need Kevin Muscat more than Melbourne Victory does - and I don't mean for the comic value. After all, in the boiling cauldron of the game day stoush, what's the point of heroics without a villain to overcome?

Peter Parker's nemesis was the Green Goblin. Batman tangoed with the Joker. Without Lex Luthor, Superman was just another buff bloke in lycra. At 37, Muscat is a diminished on-field presence but he's still the player Harboursiders love to hate.

The round one clash of the A-League titans delivered the customary sabre-rattling from the crowds. Numbers were down but not so the intensity emanating from the bays. Muscat's defending might be responsible for more leaks than Treasury these days, but in the annals of A-League villainy the Victory hardman is unsurpassed.

That can't be said for his football. Surely the day is fast approaching when Victory players stand on their own 22-feet; when the team weans itself off that tatty comforter it's been dragging around the pitch for the past five seasons. When that happens what will it mean for the future of Sydney FC's biggest drawcard, the Big Blue? Can the inter-city rivalry survive Muscat's retirement?

That's probably a question for season seven. In the meantime, an even greater test is likely to come in round 9 when Victory takes on Heart in the league's first genuine derby. Football derbies are the real deal: neighbourhood ding-dongs that set one side of the street against the other; the kind of match-ups that divide mum, dad and the kids across the kitchen table. Sydney will have their own taste of derby action when expansion club Rovers joins the A-league next season.

So could this be the swansong for the great Melbourne - Sydney dust-ups? Will the games hold the pre-eminence they once did? Maybe not. Whatever its future, the rivalry has given a tantalizing glimpse into domestic football's potential. We might not realise it yet, but you can bet the other codes do.

A good mate of mine was in the SFS crowd last Saturday. It was only his second A-League experience, and his first as a club member. It was an eye-opener, to say the least. There was something in the air that night and it wasn't Fernando.  Tribalism, he called it. Not the full Braveheart mind - but in the heat of this battle everyone seemed just a bum's rush away from dropping their daks and mooning the away bay.

The level of scorn heaped upon the opposing captain certainly came as a shock. It wouldn't happen at the rugby, he admitted. Indeed. But those who write off football fans as poor sports miss the point entirely. If the world is a stage then football is the ultimate theatrical experience.

The A-League is only now discovering that the beating drums of tribalism could be its trump card. Just a few years ago rugby fans were bemoaning the lack of emphasis its code placed on developing tribes. AFL boasts far superior numbers but for all its numerical advantage it can't register the intensity of emotion when football tribes collide.

League knows it. Rugby knows it. So does that other mob. In the wash-up of last season's A-League grand final there was a telling exchange between AFL supporters Gerard Whately and Barrie Cassidy on ABC's Offsiders. Both men attempted the impossible - to put into words the surge of emotion that gripped Etihad Stadium in the dying moments of regular time.

Whately: ...this wave of noise and the connection between football fans and their team was really something to observe... but you were in the crowd, have you experienced a 10 minutes of... and it was outright frenzy?

Cassidy: As you said - it drove the game. It kind of impacted on the way the players approached the game.

So the world's most global game is also the most tribalistic. It appeals to something instinctive and primal. There's a very good reason why fans are given inflatable clubs on the way into the stadium.

You may not have heard of the Wantok Cup - it's a football competition between three Melanesian countries. Small fry in world football terms but the name Wantoks (one talk) captures the essence of the tribe; members who speak the same language. In the A-League we're still refining the language and boundaries of that membership. For a large part fans are drawn from geographical areas with the ensuing territorial chest-beating. Adelaide United probably came closest to elucidating a cohesive spirit when  fans defiantly embraced their inner pissant during one of their club's toughest periods.

As for the Big Blue, whether it continues to grow or is surpassed by emerging rivalries, the other codes should be worried. The tribes are gathering. They're not perfect - yet. There is still a lot of work to do. For a start there's far too much fraternizing with the enemy. Players such as Sasho Petrovski breezily swap colours like they've been given a subscription to the club of the month.

So maybe that old warhorse, Muscat, still has a few footballing lessons to impart after all. You can bet he'd never skip over the border to join the Sky Blues, and Sydney would never have him - which is just as it should be.