All those who have accused Manchester United of being a one-man team for much of this season will point to the 2-1 defeat by Chelsea as evidence.

It was hard not to agree as Rooney sat high up in a glass box at Old Trafford, resting his injured ankle and watching his teammates toiling in his absence.

It was also hard not to conclude that this defeat just might be the defining moment in a title race which to date has defied prediction.

Why? Because United without Rooney looked ordinary, a tired and lethargic team carrying too many thirty-somethings in Gary Neville and Paul Scholes and Ryan Giggs.

A team, and this is rarely written about a side selected by Sir Alex Ferguson, lacking legs and desire.

By contrast Chelsea, without Didier Drogba until he came off the bench after 70 minutes, appeared rejuvenated. They dominated possession. They had the threat of Florent Malouda's pace, the consistency of Nicolas Anelka and the flourish of Joe Cole, who scored the first goal with a cheeky back flick.

They looked like a team who had come to terms with the disappointment of their Champions League exit and were determined to put domestic trophies in the cabinet instead.

United, for too long, simply carried on from where they left off in defeat to Bayern Munich in midweek.

Where was the tempo? Where was the drive and the ambition?

Well, the television cameras seemed to know. They kept returning to the sight of a frustrated Rooney.

It would be easy to point the finger at Dimitar Berbatov, a player who until now has played at Old Trafford largely without responsibility. He hasn't needed to, not with Rooney shouldering it all on his ever-willing shoulders.

Berbatov is no Rooney. He is languid and elegant. Rarely has he suggested he is prepared to break into a sweat for his £30.75m price tag.

It is why many of the United fans would preferred to have driven him down the road in the family car to Eastlands rather than lose the bundle of energy which is Carlos Tevez.

But it was not Berbatov's lack of industry which cost United. They cannot blame Berbatov for this title-jolting defeat even if he did fluff an injury-time volley from around the penalty spot.

Nor can they blame referee Mike Dean, who denied them what appeared a penalty in the first-half when Ji-Sung Park was brought down in the area.

No, it took United an exasperating hour to turn up the tempo and rev up the Old Trafford faithful.

It took Ferguson's team to realise the chance of a record-breaking fourth consecutive title was slipping away before they began to play with anything like the panache we have come to expect from them.

And, yes, then they came with the obligatory cavalry charge. But that is not good enough. Not at this stage in the season. Not even when Ferguson had every right to make use of his famous hairdryer when an assistant referee failed to spot Drogba was offside for Chelsea's second goal.

The fact is that even when substitute Federico Macheda reduced the arrears it was an effort bundled home with the help of a hand after good work by Nani. It was hardly a statement of confident intent.

So what does it all mean? It means United have now lost seven matches this season, more than any club who have won the title in a 38-game season. It means Chelsea are now 11-10 favourites to land their third Premier League title, even if they do have marginally the harder run-in with matches away at Tottenham and Liverpool to come.

It means United have hit a low spot just when they could least afford it. Mostly, it means what most of us have suspected for months, even if it would still be a brave man who called the outcome of this unpredictable season.

United cannot do without their prolific goal-scorer, their greatest inspiration, their shining light. They cannot manage without Rooney.