Back when their rivalry was at its peak, before it had come to seem a bit like the fossil of an earlier football civilisation, Arsène Wenger was asked to respond to one of Sir Alex Ferguson's more rabid asides. "Please," said Wenger, "never again put to me the views of that man. I don't want to hear his name."
Though considerable mutual respect has grown since those days of intense psychological warfare – not to mention the fabled chucking of the odd piece of pizza by the teenaged Cesc Fabregas – it is not so hard to imagine this week Wenger with his hands still clamped over his ears.
The trouble is that Ferguson has once again confirmed his status not so much as a waspish old foe, always ready to probe the weakness of a rival, but a walking reproach to any football manager who loses a stride, who fails to respond to the imperative which has plainly shaped every day of his own working life.
This, as we saw so vividly at Old Trafford on Monday night, is to constantly re-seed a winning team.
Not for the future but for today. Not according to some well-honed philosophical principles, but the need to create seamless progression while always retaining the ability to win at the highest level.
Danny Welbeck and Tom Cleverley may have much more to do to justify the optimism created by their impressive contributions to the victory over Spurs – and the enraptured welcome provided by their manager when they left the field – but what couldn't have been conveyed much more strongly was United's continued ability to irrigate a title-winning team with fresh, young blood.
In the process they held up a mirror to Arsenal's current plight in a way that almost carried a touch of sadism. Here was the second-youngest team fielded in Premiership history conducting highly-effective business against one of England's better teams.
Furthermore, it was a team operating with great composure without some of its most experienced elements and that – and here the comparison with Arsenal as they face the peril of tonight's Champions League qualifier at Udinese becomes savage – just happened to be defending the title.
If Wenger feels the touch of paranoia which comes to most victims of conspiracies of fate, he is not without reason.
The pressure to avoid the catastrophe of ejection from the Champions League, with its huge loss of revenue and complication to the signing moves he so desperately needs to make, is immense enough to shred battered nerves in any one week. Then it becomes almost grotesque when you throw in Sunday's visit to an Old Trafford which will surely be at the upper end of its bombast register.
What can Wenger do? He must, as a matter of the greatest urgency, separate himself from the feeble argument of his most devoted admirers that there is nothing wrong with his team that jet-propelled progress by the likes of Jack Wilshere (which didn't look solikely after yesterday's injury news), Aaron Ramsey and Emmanuel Frimpong will not put right.
This is borderline bonkers. Formidable prospects these youngsters may be, but can more be expected from them in one hugely crucial season than was produced by Fabregas, with a growing crisis in conviction, and Samir Nasri and his progressive yearning for other people's pay packets?
It is not likely. The signings have to be made before the transfer deadline, the agonising about value for money and the perfect deals – of which Wenger will always be able to claim a formidable number – has to be put aside for more serene days. Arsenal have now to do in barely a week something United have always tended to perform over the years. Of course it is too soon to say that Ferguson has again hit the football gold standard, but if Wenger at least wants to hear the name of his old rival this week it is not because of old wounds and antipathy but the unswervable fact that the balance of power between the pair has never seemed so remote.
Wenger's achievements will not be erased by the mountains of angst now growing around the Emirates. They will survive any nightmare in Udinese or a convulsion at Old Trafford. This is because they involved more than the winning of titles and cups. They were about a certain way of playing the game and lifting the spirits, and the memory of quite how it was achieved is surely indelible. But that was the past – and an increasingly distant one.
The problem for Wenger in this of all weeks is that the pressure to recreate some sense of that past has never been more pressing. In this sense the message from Old Trafford this week could hardly have been more timely – or potentially cruel. It said that the best way to recreate a great past will always be to live in today.