When Lester Piggott, the winner on Roberto, was booed at the Derby after jocking off a much loved veteran rider Bill "Weary" Williamson, the old horseman Lord Oaksey speculated, "there might be no man on earth less susceptible to the sound of a hostile crowd".
The same is surely now true of Sir Alex Ferguson, both in facing down the noise of a mob - or an individual.
Certainly, the indignant body language of Ruud van Nistelrooy must rank low down on the scale of Ferguson's concerns.
Above everything else he is a pragmatist. At times his optimism knows no bounds, and his belief that United are destined to win every game they play has been a fundamental part of his and the team's success. But he also knows when to fold his cards in certain situations. He knew well enough when Roy Keane's time was up and we shouldn't swallow easily his public line that the omission of Van Nistelrooy, the scorer of 22 goals this season, from the League Cup final, was simply a matter of keeping faith with Louis Saha.
Utterly irrelevant, you have to believe, was the fact Saha just happened to have had particular success this season in the competition which Ferguson would normally evaluate pretty much as one disenchanted vice-president of the United States rated his ostensibly high office - "it's not worth a pitcher of cold spit," he said.
If the League Cup hadn't been Fergie's one last chance of getting his hands on some silverware this season, Saha's regular appearance in the competition could only have been seen as a rebuke rather than a vote of confidence. However, a new wind is necessarily blowing through Old Trafford and if Van Nistelrooy's scoring figures have remained consistent this hasn't always been true of his overall performance - or apparent commitment on the field.
Last week in the rather more significant FA Cup action at Anfield, Ferguson was so despairing of the Dutchman's potential to ruffle the iron-clad Liverpool defence that he sent on Saha. Now, the sweet cohesion struck up by the Frenchman and Wayne Rooney has surely put a question mark against Van Nistelrooy's future at Old Trafford.
Inevitably, his situation has to be compared with that of Thierry Henry, whose likely defection to Real Madrid or Barcelona can only have been hugely enhanced by his beautiful performance at the Bernabeu last week.
Both long ago proved themselves wonderful signings; Henry has been the perfect expression of Arsène Wenger's work as both coach and teacher and creator of fine football at Arsenal; Van Nistelrooy has been a sustained cutting edge in a Manchester United team that Ferguson, with the acquisition of players such as Juan Sebastian Veron and Laurent Blanc, was supposed to move on to a new dimension.
You couldn't fault Ferguson on his conception; Blanc had a sublime hauteur which the United manager thought could still be perfectly expressed in the more measured football of Europe, but the great Frenchman had slowed, critically by Premiership standards, and Veron, while still capable of spasmodic brilliance, was simply not what he had advertised.
Van Nistelrooy was the redeeming confirmation that Ferguson's appetite for the big signing was still sound, a reality underlined by the certainty with which he pursued Wayne Rooney and his frustrated attempts to bring Ronaldinho and Arjen Robben to Old Trafford.
Now it is not so hard to sense that both Van Nistelrooy and Henry have their eyes on new horizons.
Maybe they feel that they have had the best of days at Old Trafford and Highbury and that in each of their cases there is left one big new challenge ... and pay deal. When the partings come, there is surely a strong case for amiability and respect. They are in their late twenties, time maybe for the last adventures, projects that can be undertaken with the certainty that when their blood was up they served their old employers superbly well.
However it works, we can be sure that Ferguson's need to win Sunday's game against the brilliantly motivated Wigan Athletic was the overwhelming consideration when he drew up his team sheet. Can anyone seriously imagine Ferguson picking less than what he considered his best team in a match that had come to be probably his most important of the season?
His decision speaks of a belief that Van Nistelrooy is judged not to be the player, or at least the Manchester United player, he was when he represented a striking arm of such force and tremendous reliability.
There was also the Dutchman's intense and palpable need to succeed. It transmitted itself in more than exuberant celebration of the inevitable goals. It was like a shot of electricity. But not at Anfield recently, and not in too many critical games. Some tough professional assessments say that Van Nistelrooy has lacked his finest cutting edge for at least a year now.
Maybe Ferguson in his relentless way does see the League Cup triumph as a statement, albeit a modest one, about the potential of a new United, with a burgeoning relationship between Rooney and the highly skilled Saha, and a significant strengthening of the midfield in the summer. In this eternally hopeful picture, the outline of Ruud van Nistelrooy is inevitably blurred. Soon enough, you have to suspect, it will be gone.
Brady lays bare all the double talk on Del Horno
The Asier del Horno-Lionel Messi controversy was briefly revived at the weekend with the Chelsea full-back's public rage over the scourge of "cheating". Enough on the issue has probably been said here and elsewhere, but one point refuses to go away. It is the appalling mutilation, if not the outright avoidance, of the truth that has become commonplace in football.
That Del Horno should question Messi's reactions, when you consider the explicit nature of his foul, and the scale of his own response to the collision he initiated, would be mind-boggling if we hadn't become engulfed by such examples of one-eyed opinion. Or had to listen to his coach, Jose Mourinho, flog the same outrageous lines by way of deflecting the impact of defeat by Barcelona and the brilliant talent of Messi.
It is also alarming to consider how much double talk passes for "comment" in that incestuous area which sees the meeting of the business partners, television and football.
Apparently Sky's chief analyst, Andy Gray, thought that Del Horno's red card was harsh and, in the studio, Jamie Redknapp blamed Messi for taking his eyes off the ball. It was thus refreshing to hear the unanimous reaction of the analysts working in the RTE studios in Dublin. Panellists John Giles, Liam Brady and Eamon Dunphy were all emphatic that Del Horno should have walked for his increasingly desperate and illegal attempts to curb Messi.
Brady, a nifty wing performer himself, could scarcely have been more forthright. "A case of beauty and the beast," he sighed drolly.