A special character came along and within weeks he had galvanised the place. He won the League Cup in his first full season. Ask younger supporters which figure brought the electricity back to Pittodrie in the mid-1970s and many will blurt out the name of the Govan knight. Understandable, but Alex Ferguson came later.
Derek McInnes stands on the brink of something momentous if Aberdeen defeat Inverness Caledonian Thistle in tomorrow's League Cup final and if he achieves it, it is Ally MacLeod he will emulate, not Ferguson.
The rest of Scotland remembers "Ally's Army" and the pied piper who led the country to Argentina and up the garden path. In Aberdeen they recall the late MacLeod with real affection as the charismatic, devil-may-care maverick who struck the place like a lightning bolt and caused so much excitement that the Scottish Football Association poached him to manage the national team. MacLeod preceded Billy McNeill who preceded Ferguson. Aberdeen were turned around in the 1970s and it was MacLeod who provided the first shot of adrenalin.
When it come to MacLeod and McInnes as personalities, there is no comparison. MacLeod was eccentric, a happy showman, at times a bit of a cheeky rogue. When McNeill replaced him the players - the likes of Willie Miller, Joe Harper and Bobby Clark - enjoyed the thoroughness and professionalism of his training and preparation after MacLeod's sometimes harum-scarum approach. But MacLeod had the players eating from his hand. His man-management was so inspired they would have done anything for him. Together, they delivered the League Cup after six-and-a-half years when tumbleweed blew through the Pittodrie trophy room.
McInnes is no showman and will never make public declarations about wonderful, magical Aberdeen doing this, that or the other. He is cautious with the media, constantly playing things straight and withholding his wit and most revealing insights for times when the cameras and microphones are well away. He has never set out to be a colourful salesman yet he has magnetised supporters even more powerfully than MacLeod could.
Those 40,000 fans gravitating to Parkhead tomorrow to follow the Dons? They will be there because McInnes has restored their self-respect and delivered a team in which they dare to believe for the first time in two decades. Craig Brown, the previous manager, began to mould the current squad but it has taken McInnes to elevate them to a new level.
Everything has built to the crescendo of the season's first cup final. The most persuasive evidence of Aberdeen's improvement has not been their ongoing campaigns in both cups but the fact they sit second in the SPFL Premiership, having finished eighth last season. They have an inarguably strong group of players and the key ones are secured on good contracts, as are McInnes and his assistant Tony Docherty after yesterday's announcement that they had signed extensions until 2017.
Niall McGinn, Peter Pawlett, Adam Rooney, Jonny Hayes, Ryan Jack, Mark Reynolds and Willo Flood should all be wearing red for another season at the very least. The building blocks are in place.
Having waited since 1995, the longing to see a trophy win is unbearable. This final against Caley Thistle has all the traditional weak points which, when pressed, have tended to make Aberdeen buckle: they're strong favourites, they have a huge and expectant support, the consequences of defeat are unthinkable, and some are waiting for them to fold like they have always done since the mid-90s.
But all of that applied to the semi-final against St Johnstone too. The 4-0 win that day caused many to look at McInnes with even more respect. It was the first semi-final Aberdeen had won in six attempts spanning 14 years.
"As well as we've done in the league, if we had lost that semi-final it would have been difficult to convince people," McInnes said. "Not that we need to convince people; we just need to convince ourselves. But it was a hurdle to overcome and we did it in style, which helped us go into the Scottish Cup tie at Celtic Park with confidence [Aberdeen won that as well]. I think if we can win a trophy that will give these players a taste of success and they'll want it again. Reaching this final has caught everyone's attention. It's given huge encouragement to everybody in and around the club. Everybody at the club has been busy, not least the ticket office and commercial staff trying to sort everything out and make sure we are ready to cater for everybody.
"That's the way you want it to be. The energy about the club, the energy about the city, is exactly how we wanted it. We want that to continue and the best way for it to continue is to keep getting to cup finals and hopefully winning.
"It's such a huge game for everyone but there's still the professional element of the players and the staff and that's the same: it's doing the job. I don't believe you can play at your best if you have any fear or you start thinking of failing. It's always about believing you're going to win, not having any anxiety. The whole thing about fear and anxiety, that's for fans. It's for them to get nervous. Regardless of whether we're winning or losing or drawing, just trust what you do and trust that you are good enough.
"I believe they players are good enough. They should take confidence from the quality of player around them, their team-mates. But just because they're having a good season, just because they're talented, doesn't mean to say it will automatically come on Sunday. We have to make sure they recognise they have a responsibility to get themselves ready to play. Don't let the game bypass you, don't waste the opportunity to show how good a player you are."
MacLeod won the 1976 League Cup exactly one year from the day he was named Aberdeen manager. McInnes has the chance to do so nine days faster, having been appointed on March 25 last year. They are different men from different times, but they are united by the speed of their impact and the gushing gratitude of their people.