Say what you like about the Old Trafford agitator-in-chief. Call him cantankerous and self-serving. Throw in, too, that there have been times this season when his team have looked so far past their sell-by date that the top place in the Premier League has appeared less an achievement than a rebuke to all challengers.
But when you've done all of that, where does it leave Sir Alex Ferguson's closest rival, Arsène Wenger?
Crushed, you have to say, by the latest evidence that, while he continues to search with ever-increasing desperation for a hard edge to some often beautiful football, his greatest rival retains an astonishing ability to redraw his football horizons even in the most unpromising circumstances.
When you look at it this way, United's FA Cup sixth-round defeat of Arsenal assumed a significance out of all proportion to the winning side merely securing a berth in the semi-finals of a tournament that all the leading clubs long ago designated as a trophy of convenience rather than need.
This was an important litmus test for both state-of-mind and credibility and Ferguson won in a way that breathes fresh importance into the extraordinary fact he continues to fight on three fronts: leading the league, with the possibility of a Double, and a chance of a Champions League quarter-final place that was sharply enhanced by the injection of morale against Arsenal.
There is another reason for United optimism. It is that, at last, Wayne Rooney is looking more than a little like Wayne Rooney.
This, surely, is where you start and finish with the bonuses of a performance from a team which, when announced, resembled a skeletal parody of the club's old deep-running strength.
The subsequent choreography may not have quite matched anything dreamed up by the late Michael Jackson but, compared to recent performances in Marseilles, Stamford Bridge and Anfield, it was filled with life, even vibrancy.
Nemanja Vidic brought back all his strengths. Beside him Chris Smalling produced another superb performance, the Da Silva brothers played with a wonderful relish and optimism and Antonio Valencia's resurrection in the second half was filled with promise.
All of that was an unexpectedly lively and competitive cocktail stirred from a no-hope teamsheet, but it was Rooney who was the revelation.
His relations with his boss are reported to be still on the south side of amiable but if there is any substance to the suggestion that he may be on the move in the summer it will, if Saturday's form is maintained, be as something other than a glum excuse for the player who tore through most of last season.
Rooney's superb football intelligence and technique marked both United's goals. First, he intervened in the rampaging attack of the boys from Brazil with a perfectly flighted cross that Javier Hernandez met so well an inspired Manuel Almunia could only push the header into the path of Fabio.
Then Rooney put the game beyond Arsenal with a flick of his head from an acute angle. It was a goal of fine judgement and nerve, and it said that Rooney was once again in charge of himself – at least on the field.
There was one fleeting cameo of the manager and the player on the touchline, an earnest Ferguson and a Rooney swigging at a water bottle and smiling broadly, perhaps at the rediscovery of the possibilities of fresh plunder.
The chances of such a relaxed interchange between Wenger and his players were doomed from the moment it became clear that Ferguson's decision to field seven specialist defenders, with John O'Shea and Darron Gibson in the midfield, did not exclude the ambition to launch seriously attacking football.
Wenger's despair is now excruciating. He couldn't complain of any lack of effort in the absence of Cesc Fabregas. Samir Nasri, Jack Wilshere and Robin van Persie at various times all announced their formidable credentials but they never threatened to dislodge United's conviction.
The Arsenal manager insisted that his team had matured competitively before three crucial tests of their ability to transform six years of varying levels of potential into the hard coinage of authentic achievement. Yet in two weeks they have had three of four possible prizes swept from their grasp.
Wenger's toughest critics are now saying that this isn't so much a bad run as a statement of terminal failure, and who can say they do not have the most wounding evidence?
Certainly, Arsenal are yet again impaled on a special dilemma. It takes extremely refined nerve and a unique degree of detachment from the imperatives of today's football to keep on saying that it is enough to play lovely football in a fine stadium and on the back of an exemplary business model.
But how much of self-satisfaction would be happily exchanged by Arsenal fans at Old Trafford for the sense that they had a team infused with the same degree of that conviction which had so plainly returned to United at such a pivotal moment in the season?
In so many ways, Arsenal are an example to the rest of football. It is the club that pays its way and refuses to be deflected from the ultimate priority of playing superior football.
But then, when does such idealism founder against harder teams, harder ambitions? When does the promise of a Wilshere or an Aaron Ramsey become too much of an old and unfulfilling story? For how long can you mortgage the future?
If you wanted to pick a random time for such an appraisal, last Saturday night at Old Trafford would have done well enough. Yet again, some of Arsenal's football was as thrilling as any fan could want – but once more it ran through his fingers.
Nor does it help that it is United, upright at the bar again, who have to be disposed of in the last chance saloon of the Premier League. It is just too easy to imagine more smoke for Arsenal – and more tears.