James Lawton: A resurrection of sorts, but United did not answer critics, they underlined the malaise

How many blips, over a number of years, constitute a life-threatening disease?

United, if they knew it or not, were confirming every last muttering of rage that players who had received so much could give so little over the course of two full seasons.

When they had to, when their professional reputations were on the floor; when they had become bywords for the neglect of standards which should be taken for granted in players living so high on the scale of football's rewards; when they were threatening to reduce to ashes the work of one of the great managers, a man who had backed them to the very edge of his credibility; they took on and, whatever the revisionist quibblings of Jose Mourinho, beat the most richly endowed football club on earth.

Now when they next go out to do their professional duty - at Charlton Athletic later this month - Ferguson can ask with huge moral force the question which is presented to every seriously rewarded professional in any walk of life: what are you going to do for me today?

Are you going to make a nonsense of your station - and your talent - as you did against Middlesbrough, beaten by Everton at the weekend after looking like the wonder team of Europe eight days earlier when ripping apart Rio Ferdinand's version of high-quality defence, and then against the profoundly mediocre Lille in Paris? Or are you going to do something for which you receive what most other occupants of the planet would consider astonishingly generous reward? Are you going to play as though it vaguely matters?

Whatever you thought of Roy Keane's diatribe, however much you believed it flowed from personal frustration and a sourness of spirit inexplicable in a man who has drawn from the game quite as much as he has contributed - which is rather a lot - the substance of his complaint was reinforced rather than demolished as Chelsea's unbeaten Premiership run suffered the same fate as Arsenal's on the same ground just over a year earlier.

With the exclusion of some of the cruelties directed at young players - Darren Fletcher and Alan Smith certainly showed against Chelsea that they may just turn out a little better than Keane might think - the Irishman was returning to a point that could have been made at any time since United won their last title two and a half years ago.

It was that the most critical problem at Old Trafford is not the disappearance of competitive talent - Wayne Rooney, Cristiano Ronaldo, Ruud van Nistelrooy, Paul Scholes, Ferdinand, when his head is reasonably attuned to the rest of his body, John O'Shea, in the form he showed when he first came into the team, utterly contradict that notion - but a failure to remember what it was that first created all of the club's success.

It was hunger and pride renewed game by game, challenge by challenge. Some may now say that what happened against Boro and Lille were blips. But then how many blips, over a number of years, constitute symptoms of life-threatening disease? Remember what happened when Arsène Wenger's dream team were turned into a rabble at Old Trafford last season? United went to Portsmouth, who were fighting for their Premiership lives, and lost.

The pattern is deeply entrenched and victory over Chelsea should detach no one from the reality that the performance against Charlton - and then every effort until the end of the season - is the only legitimate guide to the significance of Sunday's triumph.

When Arsenal were pushing back the barriers of domestic performance the season before last, when some were talking about the best team ever to grace English football, who was it that stepped up and played them into the ground? United couldn't stop their unbeaten League season, but they could overwhelm them with their desire in the FA Cup semi-final at Villa Park.

Earlier this year, United went to Highbury in the hope that they might complete the double over Arsenal and make some kind of challenge to the emergence of Chelsea. The first part of the job, helped hugely when Keane faced down Patrick Vieira both in the tunnel and on the field, was completed magnificently. But the title challenge dribbled away.

Grace in defeat is not a striking quality of Mourinho, any more than it is in Ferguson, but on one point he couldn't be contradicted. He had no reason to fear for the future; on balance his team had been stronger, at least before his own Ranieri-style meddlings in the second half, and if they lost, it was not because of any abandonment of the values that have made them overwhelming masters of the English game.

Chelsea do not have a Rooney or, at his best, a Ronaldo, but they do have the underpinnings of a great side. They do work for each other not in some heightened effort but in the course of a normal work shift. They know, now, what it takes to win a title; they know that one performance is as important as another.

It is here where Mourinho has shown his brilliance as a coach and a motivator. As to his tactical flair, some of us believe the jury should not rush to judgement on the "Special One". His patience in the big matches is not always exemplary. He went to the long ball against Liverpool in the Champions' League semi-finals when pressure was at his highest, and on Sunday the injection of Carlton Cole and Shaun Wright-Phillips did nothing to augment Chelsea's growing edge. Where he scores so heavily, though, is in the consistency of his passion and capacity to motivate. Not for a second did a Chelsea head drop in the restored clamour of Old Trafford.

Can the latest resurrection of Manchester United begin to hint at such professional commitment? Yes, but precisely and only in the way of a beginning. It cannot be any more than that because we have seen it so many times before in the course of their decline from what they used to represent. That was when titles were not so much an achievement as a right.

We know they can beat Arsenal, their original nemesis, when the mood is on them and now we know they can beat Chelsea. But how sure can Ferguson be about his team when they go to Charlton or Blackburn or Bolton? Look at the defeats that disfigure recent seasons. When they lost once before to Middlesbrough, Keane believed it cost them a title and he most vociferously blamed the sloppiness of Juan Sebastian Veron. It was reported that Keane had to be dragged away from the Argentine. All teams have hiccups, you may say, and is true enough; but the best of them, the champions, play through them as though they have been no more than victims of some isolated impertinence.

It is a long time since we have seen that from United. What we have are these periodic eruptions of pride and fight and, let's be sure about this, fear.

It used to be true that there were few less secure occupations than that of the professional footballer. A pro had to be coaxed into the belief that his place and his living were safe. Heavenly contracts have done much to change that, but there is one residue of the old days. It is the stimulation that comes when a player faces the prospect of public humiliation, when all the underpinnings of his status, his extraordinary good life, might just be dragged away.

If such a prospect is unlikely to ever cloud the vision of the prodigious Rooney, it seemed real enough to some of his team-mates against Chelsea. Rooney played as he always does, with a raging appetite and an instinct to hurt the opposition at every opportunity. This time, though, the responses of all his team-mates were more urgent, more driven. But then this merely takes us back to that ultimate question. What are they going to do today and the next one and the one after that? Not until we get the answer can we know if United's defeat of Chelsea was anything more than a bandage for self-inflicted wounds.