Talking Point: Where next for United?
The mind struggles to cope with the image of someone other than Ferguson patrolling the touchline at The Theatre of Dreams; eyes bulging, jaws clamping up-and-down mercilessly on a peice of chewing gum, face purple with rage, but this day was always going to come.
For me in particular, at 21, it seems even more alien. Like all of the United players, I've never known anyone else.
Even Ryan Giggs, rapidly approaching 40, has never played under anyone but Sir Alex during his own astonishing United career.
The big question, of course, is where to next for United?
You would struggle to buy the idea that Ferguson has dropped this bombshell overnight, leaving the United board of directors in the lurch. This decision has been coming for months and no doubt Ferguson has kept the board in the loop with regards to his decision well in advance of the public announcement.
One would also struggle to comprehend a situation whereby the United board have not already identified and approached their number one target. This is Manchester United and as Sir Alex has himself pointed out down the years, no-one is bigger than the Club.
A replacement therefore, has surely been lined up, keenly awaiting the public announcement that they will succeed the King of Old Trafford after his 26-year reign.
It's an unenviable task, to the point that it's almost a poisoned chalice. How on earth do you follow the incredible success Ferguson has enjoyed? Whoever comes in will immediately be compared to their predecessor and will be expected, rightfully so, to stick to the same foundations of success that steered the Scot right.
Jose Mourinho is the name that immediately springs to mind. But, according t oa number of tabloids, the Special One's return to Chelsea is a formality. How true that is, remains to be seen, but I for one find it hard to believe that Mourinho would be so close-minded about his destination as to wrap it up before the current season even ends.
The problem with Mourinho is his own maxim: nobody is bigger than the Special One. Unfortunately at Old Trafford, that kind of bravado will simply not wash.
Mourinho is a fly-by-night kind of manager, chasing trophies and personal glory at each of the clubs he has managed - with the arguable exception of Chelsea - would United's directors really want a man so hell-bent on pampering his own ego and stuffing the top-pocket of his sartorially excellent blazer with as many medals as possible before dancing off into the sunset chasing a new conquest?
Perhaps United is the club to make Mourinho settle down and buy into a long-term project? His options are afterall, beginning to run out.
Moreover, one of the firmest principles of Sir Alex's reign has been the trust he places in youth. From the original 'Fergie's Fledglings', right up to the likes of Danny Welbeck or Nick Powell today.
A by-product of Mourinho's urgency for success is that he does not invest in the future by buying young players with potential. He buys superstars for the here-and-now. And, whilst United undoubtedly need a household name in the centre of midfield to help Michael Carrick out, the continued development of their youngsters cannot be compromised.
Which leads us to David Moyes. By no means adverse to youth development - it was he afterall who sold Wayne Rooney to Ferguson - and someone who would undoubtedly buy into the ethos of the club, sharing a number of Sir Alex's core principes to boot.
There are some concerns over Moyes though: he isn't a 'big' name; he might not be a wallflower, but he's no thorn bush either. United have always been defender voiciferously by Ferguson, whether right or wrong and Moyes gives off the impression of a keen diplomat.
Pep Guardiola is of course set to replace Jupp Heynckes at Bayern Munich, but the outgoing boss is far too old to fit United's remit.
Guardiola's Budesliga nemisis Jurgen Klopp is somewhere between Moyes and Mou in terms of personality and stature, but is a man of his word and has said he will stick with BVB for the duration of his contract, as he did with first club Mainz.
United have said the announcement will be made soon. In the mean time, the football world waits with baited breath.