BACK in 1981, Liverpool took a right hammering from Manchester City. I wasn't long at the club but I have a vivid memory of the consequences. Anfield was a very uncomfortable place for weeks.
Joe Fagan, who was then the No2, called for a meeting and Bob Paisley agreed. The senior players like Kenny Dalglish and Graeme Souness were hauled in and told that they had the responsibility for putting things right.
We beat City 5-0 in the return and Liverpool won the league and league cup double that season. I have no doubt that it was that 3-1 defeat which was the tipping point.
Paisley was rebuilding his team and people like myself, Ian Rush and Mark Lawrenson were young and inexperienced. Many said at the time that we were too young and too inexperienced.
But Dalglish cracked the whip, lessons were absorbed and we were stronger for it.
I wonder who Alex Ferguson will call in and haul over the coals? If there was ever a need for his hairdryer, it's right now.
He could do with Roy Keane in his dressing room, because he will need someone of stature and influence to bring them through what is a horrible experience for any professional footballer and even more bitter for lads who don't often have to deal with it.
This was a disastrous collapse by any standard. I know Manchester City were very, very good but not that good.
Ferguson's players threw in the towel far too early for my liking and, when they did that, they exposed a big problem for their manager.
Ferguson doesn't have a Dalglish or a Souness, and while I'm sure he will ask for a chat with lads like Ryan Giggs, Wayne Rooney, Rio Ferdinand and Nemanja Vidic, I don't think any of them carry the same kind of weight.
Ferdinand is a spent force and that is now clear. Rooney tried to leave the club and caused absolute chaos just over a year ago and Vidic too has had moments when he seemed ready to walk away. Giggs has never been a forceful character.
I can imagine what it will be like at Old Trafford in the days to come. Nobody expected a beating of the scale Manchester United experienced and it will come as a great shock to the system.
Everyone involved, from the tea lady up to the boardroom, will feel the pain of this defeat and the fear it brings with it.
The club has faced challenges from Arsenal and Chelsea before and faced them down but this is too close to home.
In truth, Manchester United have been overdue something like this and it took an investment of resources beyond anything we have seen before in the Premier League to expose the element of wing and prayer that Ferguson has been running on for so long.
Over the past few seasons, Manchester United have seemed to stumble along, still winning and still packing away the medals but not with the same authority they showed in previous years.
They were lucky that Arsenal, Chelsea and Liverpool were in turmoil of one kind or another and for Ferguson, Manchester City probably seemed a long way off the kind of stability needed to make a realistic challenge.
His fresh, young team began this season with a bang and it looked like Ferguson had pulled off another miracle and produced instant winners from a very inexperienced pool of players.
When they are good, they are very, very good but when the pressure came on in a big way, they folded.
Ferguson spoke about matching Barcelona when the season started and how they have set the standard he must follow and beat.
It is now more than evident that he must first deal with a more immediate threat next door before he can hope to cope with Mr Messi and Co.
This was a huge statement from Roberto Mancini and his team about their ambition. Best of all from his point of view, they beat Manchester United almost senseless without Carlos Tevez.
For me, Tevez threatened Mancini's position as manager and if there was any doubt at all about who is the dominant force in that relationship, that is no longer an issue.
Mancini is now stronger than he has ever been at Eastlands and maybe he needed a big win like this to achieve that.
The Tevez affair could have swung either way. Imagine if this result had been reversed. I have no doubt that there would be many City fans thinking wistfully about Tevez this morning if that had happened, but this remarkable win gives the manager all the cards.