FOOTBALL, like fashion, moves in cycles. Green is the new black - or at least it seems to be for referees - and trends change so quickly it's often difficult to keep up.

Still talking about Arsenal versus Manchester United? God, that was so last season.

Like ponchos and pashminas, the sparring of Sir Alex Ferguson and Arsene Wenger lost its cool with the advent of the summer sales.

Now, there's only one thing that the trend-setters are talking about. If it's happening this season, it must be Arsenal against Chelsea.

Despite their recent blip, Arsene Wenger's side remain the Premiership's style gurus.

Thierry Henry even looks like a model and Arsenal's football swaggers with an arrogance borne of grand design and perfect execution.

But, just as some of London's oldest fashion houses have had to fight off the competition from time to time, so Arsenal have found their status challenged by a group of cocky upstarts from the King's Road.

Chelsea's flash, brash style might not appeal to everyone, but in Jose Mourinho - and isn't he one cool customer - the Blues have found an artistic director able to turn expensive raw materials into a stunning finished product.

The two sides meet at Highbury this weekend and, while the current campaign is yet to reach the halfway stage, what happens tomorrow could determine where the Premiership trophy is headed in six months' time.

It would be dangerous to write any team off with 19 matches still to play - especially one as talented and driven as Arsenal.

But, if Chelsea win tomorrow, they will be eight points clear of their London rivals. Given that they've only lost once in the league all season, that would be quite a margin.

It would also leave Arsene Wenger's side facing its biggest crisis of the last two years.

Since losing at Old Trafford in October, Arsenal have drawn with Southampton, Crystal Palace and West Brom and lost to Liverpool.

Hardly title-winning form, but Wenger has been able to write a nightmare November off as a temporary blip on an otherwise relentless charge to the championship. Lose at home to Chelsea though, and that simply will not wash.

Defeat tomorrow would represent more than another setback. It would confirm the shift in power that has been evident in the last two months.

With Frank Lampard making the surging midfield runs that were once the preserve of Patrick Vieira, and Arjen Robben eclipsing Robert Pires as the Premiership's wing wizard, Chelsea are increasingly looking like champions in waiting.

But, before they can end a 49-year wait for the title, the Stamford Bridge outfit must prove themselves against the best. At the moment that's still Arsenal - but it might not be for long.

They say that the best things never go out of fashion, and Arsenal had better hope that is the case. Otherwise, tomorrow could herald the arrival of English football's latest supermodels.

For the last 18 months, the domestic game has been decked in red and white.

By May though, blue could the only colour in which to be seen.