DAMIEN Duff will tomorrow catch a glimpse of whether he made the right decision to join Chelsea's Roman revolution.

Money talked for the £17m Republic of Ireland winger in the summer as he opted for a move to Roman Abramovich's Chelsea despite reported late interest from Manchester United.

Duff insists an offer from United was not forthcoming and that he was not aware of any interest from Sir Alex Ferguson.

But he does admit that once he was aware of the kind of money being splashed out at Stamford Bridge the decision to choose Chelsea became easy.

"That spoke volumes," he said. "It's clear that the aim is to be the dominant club in the country. You don't spend £150m to be runners-up." Indeed, for all United's home dominance, the champions simply cannot compete with the West London club's immense spending power.

If Chelsea lose tomorrow - thereby losing valuable ground in what is already looking like a three-way title race - Russian billionaire Abramovich will no doubt throw more money into the club until the Blues are in a position to compete.

However, if Chelsea beat United for the first time since their 5-0 win back in October 1999, doubts about their title credentials will well and truly be put to bed - at least until they lose their next match.

And it is upon such a fragile foundation that Chelsea fans should view tomorrow's 'title-decider.'

Indeed, until skipper Marcel Desailly lifts the Premiership trophy, doubts will always remain about Chelsea's title credentials.

Manager Claudio Ranieri has already performed miracles this season by forging such a vast array of multi-million pound talent into a such a potent Premiership force in such a short space of time. But Chelsea have beaten United before while Alex Ferguson's side are certainly no stranger to clawing back seemingly unassailable leads - just ask any Newcastle fan.

The winning mentality that Ferguson has fostered so carefully at United cannot be lost within a season and such desire cannot be bought like a player - even one as expensive as Duff.

Beating United tomorrow would be a massive boost to Ranieri's side. After losing to Arsenal already this season at Highbury, it would provide the Blues with the unshakeable belief that they can compete on a level footing with their title rivals.

But away matches against London rivals Fulham and Charlton - games that Chelsea have struggled with in the past - will provide a more effective barometer of just how much Abramovich's millions have bought him.