Dejected United leave Rome in ruins | Night to remember for Barcelona | Ronaldo and Co lose their way | Debate: Did Ferguson get his tactics wrong? | How Barcelona rated | How United rated | How the action unfolded | Rooney: we lost to best team | Henry reaps reward with new friends | Simon Barnes | Patrick Barclay | Giles Smith | Tony Cascarino | Key moments | Graphic: errors cost United dear

Now we know. Now we know why Sir Alex Ferguson hasn’t given himself up to the life of a living national treasure, wine-bore, film-bore and racing wannabe. Now we know why he hasn’t gone for the ambassadorial sinecure, smugly undermining his successor while flying first-class to unimportant meetings. Now we know why the grandchildren and Lady Ferguson have been waiting so long for his exclusive attention.

It was to take his rightful place. His place as the greatest club football manager that ever drew breath. So that people will be able to say this thing without a trace of argument, without a scintilla of irony: Ferguson really was the best, you know.

The best ever. And those with other favourites, with alternative candidates, will have to say: You’re right. It’s beyond contention. It’s a fine, noble aim, and it has taken Manchester United to great things, but it also took them last night to despair.

As the events unfolded in the Champions League final between United and Barcelona, the matter of Ferguson’s true stature in the game was still in doubt as the final whistle blew. Barcelona’s ultimately straightforward victory means that any idea Ferguson has of greatness beyond all others must be put on hold. That will irk him.

Ferguson’s place is still ever so slightly below the very best of the best, if you are using objective criteria. If you are sticking to the simple sporting matter of prizes won, then the outstanding candidate in England and in Europe, and therefore (probably) the world is Bob Paisley. Paisley is still the only manager to have won the European Cup three times, doing so with Liverpool. He also won the league six times in nine seasons.

You can argue that this beats Ferguson’s strike-rate of 11 titles in 22 years, but, really, you have to take longevity as an aspect of greatness. We probably have to accept that Ferguson has the greater domestic record (and let’s, in the modern manner, forget cups). So it was clear that the road to unimpeachable greatness could only lead through the gateway of a third European Cup. Ferguson had two. Last night, he went into the final needing one more to make that subtle but irrefragable transition: the one in which you pass from seriously bloody good to great. The one in which you shift from being a chapter in the history of your club to being a chapter — and a long one — in the history of the game.

So last night, as play began, greatness was in Ferguson’s grasp. But here’s the hard thing: once that whistle blew, there was nothing whatsoever he could do about it. At the moment of destiny, everything slipped beyond his control. That is what management means and all of a sudden it was possible to understand why all managers end up a trifle mad — and why, for most of them, this isn’t a terribly long journey. In the end, it is other people who create or destroy your claim to greatness. If you think about that for too long, you go nuts.

Last year, in Moscow, that crucial second European Cup was almost snatched from Ferguson’s grasp by a ghastly error from Cristiano Ronaldo. The Portuguese is a player on whom he had staked his reputation. Both had prospered hugely from this immense and courageous punt, and yet, when it really mattered, Ronaldo reverted to the showboating fop of his early days and, in the shoot-out, took a smart-arse penalty that was saved.

Greatness can also be removed by a decision of a referee, and whether the decision is correct or not hardly matters. The power these men have over Ferguson and his destiny is dizzying, almost incomprehensible. How could anyone live with it? One blast of the whistle and Fergie’s rightful place is snatched from him. No wonder Ferguson, like most managers, is principally remarkable for impotent rage.

One player can lose everything in a moment of distraction. Anderson’s slip-up for the first goal, the referee’s refusal to send off Gerard Piqué for body-checking Ronaldo. These matters are beyond planning, beyond computation, beyond the scope of management. And yet it was these things that left United chasing the game after ten minutes in which they had looked unbeatable.

If the United players looked impotent when Barcelona played keep-ball, how much more impotent did Ferguson feel? This was his big chance, and such chances don’t come for the asking, as Ferguson knows better than anyone, Paisley included. To sit and suffer while the moment of your greatness flickers, that is the lot of every manager who ever aspired towards excellence.

So Messi bagged Barcelona’s second, proving for all time that for every manager, no matter where he measures on the scale of greatness, football is hell. Bloody hell.