Now though, that little extra something has gradually eroded. You can see it is something they cannot find any more, at least not consistently. It is the difference between a team which is really successful, and the team they are now. This is not jumping on a bandwagon. Even before Roy Keane's interview, the whole atmosphere there had changed. People were getting frustrated with each other, you could sense they had come off their peak. I don't mean they have lost the plot or suddenly become useless. They are still a top team, but they have been so successful, so consistent and so ahead of the competition that it becomes unsustainable. Perhaps it is a generational thing, perhaps United's time has passed.
This is why tomorrow's match against Chelsea is so important for United. They have always had this resilience. When they face a big challenge, they have produced a big performance, they have proved people wrong. So tomorrow, the performance is important as well as the result. I would have expected Chelsea to win even before the events affecting United this week, because Chelsea are so good. So it is as much about how United play, and if they play as they can they can win.
They are at home, which might help, but when I think of the best United teams I played against, it didn't matter where they were, they played the same way. It was the same when I was at Blackburn, when we were really flying. We played home games the way we played away, with the same philosophy. It was confidence.
Playing United you always felt that, even if you scored, they would force a chance to level it or beat you. That happened to me countless times. They always wore you down. They did it that many times that it wasn't luck, it was will. It is where the psychology comes into it. They were a machine and when the pressure starts to bear, you make mistakes. Your clearances are a bit more rushed, you give the ball away. And the more pressure that they put on you, the harder it was to escape it. It becomes a vicious circle.
EARLY GAMES So good they beat us with hangovers
Much has changed since I first played against United in November 1990. We won 3-2 at Old Trafford, quite a baptism. The rest of the Chelsea back four were Gareth Hall, Jason Cundy and Ken Monkou.
It was a further six matches before I earned another win bonus against them by which time I was at Blackburn. We had some excellent close-fought games with them but the first one, in May 1993, was embarrassing. It was the night after they had won the League and they were still showing the effects of celebrating. It was a strange atmosphere and they were not that bothered, but though we scored first they won 3-1. They were that good then they could beat us with hangovers.
We beat them once in my time at Ewood Park, Alan Shearer scoring twice in April 1994, but it only delayed their championship. The following year we won the title but lost home and away to them, and in the Charity Shield. The year later Roy Keane was sent off against us, but they won. I think one of his bookings was for fouling me. He came diving in and as I jumped out of the way I caught my studs on his head. He has always been all right with me. He didn't go out of his way to make enemies, he just got stuck in.
At this time they really did have that edge. They did not like being behind and the tackles would start flying if things weren't going their way. I once had to hurdle a two-footed challenge from Eric Cantona. He used to lose it sometimes and that was one of those occasions.
BACK AT CHELSEA A goal to savour, and how Wisey got Nicky Butt sent off
In 1997 I went back to Chelsea and I scored in an FA Cup tie against United. It was one of my better goals, a chip over Peter Schmeichel from outside the box. Unfortunately we were 5-0 down at the time so I couldn't really celebrate it. We finished losing 5-3.
Two seasons later came redemption as we beat United 5-0. We tore them to pieces but we could do that then if we played as we could, not making silly mistakes. I didn't score, although I did put Jody Morris through for the fifth.
The most notable incident was between Dennis Wise and Nicky Butt after 20-odd minutes, by which time we were already 2-0 up. There had been a scuffle in the tunnel the previous year. I was already in the dressing-room, but there had been a few handbags and apparently Nicky had done something against Wisey's code. So Dennis clattered him. Then he bent over him, grabbed Nicky on the inside of the thigh, and said: "That hurt didn't it, you ginger bastard."
Nicky jumped up and went for him. Wisey got booked but Butt was sent off. That started a war between them in which, after a couple more games, I tried to be UN peacekeeper. I spoke to Nicky at an England get-together and said: "This is ridiculous. Why don't I say to Wisey, 'Let's call it quits and move on'?" Nicky said: "Fine. It is ridiculous and it's doing neither of us any good."
So I went back to Chelsea and spoke to Wisey. He was having none of it. "Next time I see him I'll kick him straight away," he said.
At this time the United player that I was most concerned about was David Beckham and I still think they miss his influence. Beckham worked very hard but the team worked hard to get him space to cross. And when he did, bang, goal. I played against him a lot and enjoyed it. I knew he was not quick enough to run away from me so I could get close. He still scored a few times but he drifts a lot and you would have to hand him over, then Scholes would come out to the wing. They were so fluid they were hard to play against and their workrate was phenomenal.
To get him space, Giggs would carry the ball forward and everyone would drift over. Then they would switch it. I can see it now. Giggs to Keane or Scholes, one touch and out to Beckham. He'd take one touch and by the time you got out to him the cross was already coming back in because his delivery was so good. His absence has shown his importance. Cristiano Ronaldo has not replaced him, and the way the team plays now does not allow anyone to play out there with the same freedom.
The United side that won the title three years in a row was outstanding, but the fact we were rivals created a tension, as was shown by Nicky Butt's sending-off. They still won the title that season, but we continued to do well against them and the meeting at Old Trafford the following season, September 2000, is one of my most memorable games.
It was Claudio Ranieri's first game in charge. He had very unusual techniques including a fitness trainer with all these different drills. It's funny how you get a different response sometimes. They were successfully defending their title that year but we played very well. We scored first, went 3-1 down, then drew 3-3. People said to me afterwards, "That's the best you've played for Chelsea," and it was a game I had a lot of involvement in defensively and attacking.
The build-up was surreal. It was a morning kick-off and Ranieri had this strange idea you had to wake your body up before a game by stretching for four hours beforehand. So we were in a conference room at the hotel stretching at 8am for 30 minutes. You want to get rest before a game like that and we were stretching and running on the spot, the lot. Then we went for breakfast. He thought it would wake us up. I thought a cup of coffee would do the trick. He did this for a while, but you actually felt tired afterwards and at home games we'd have to get there so early. Eventually we talked him out of it. My last game against United is not such a good memory. It was the final game of last season, for Southampton, and losing sent us down.
PLAYING AGAINST FERGIE A bad loser, but always a football man
We beat them once at Southampton and Sir Alex was very humble in defeat. I always got on well with him. I've always admired him. He's a football man, he likes players, he loves the game. When you played against United you always felt you wanted to impress him. Not because you wanted to sign for them but because he was the man, the Godfather.
He is a bad loser by nature. I'd see him in the manager's office when I went to say goodbye. He was a different person when they'd lost. He'd take it personally. The worry for him now is how much time does he have to recreate what United had? How bad does it have to get before it gets better? It must be really difficult for him. He has spent a lot of money on a couple of individuals who have not performed. Wayne Rooney's young so he will be inconsistent, Rio Ferdinand you would hope would take a lead. That's where Alex Ferguson will be focusing. Rio is one of the top defenders in the world. He should be taking responsibility in the absence of Roy Keane and Gary Neville.
There is such a pressure on United to maintain their high standards - it is whether you can do the repairs without closing the building down. Their players reached such a standard that there is no instant replacement. Even if you brought in Michael Ballack to replace Keane, he would still have to find his feet in terms of the team and the English game. Even Frank Lampard would need to adapt to the team. Sir Alex has a job on his hands.
On top of this, he has the Keane interview to deal with. His alleged comments are counter-productive. There's obviously something between Roy and the club going on. He's never afraid of saying things but, if he's got a fault, it's his timing of them. He's been their heart and soul and it's his responsibility not to damage something he's helped to build. United have always been good at keeping it in-house. They have always shown this resilience against the outside world, but that's hard to do when the criticism is coming from within.
The other problem Sir Alex has is how the team plays. What used to make them so hard to beat was that they scored goals from so many different places. They played a 4-4-2, or really 4-4-1-1 and always had a striker who could score a hatful but did not rely on him. They had a philosophy: If you score three, we'll score four. That suited the football of the period but teams defend better now, they are more organised. United are less aggressive now and maybe it has brought about some uncertainty for those players who were involved when they were free spirits, like Ryan Giggs and Paul Scholes.
Chelsea's formation of 4-3-3 is perfect for now, maybe for this generation. I think Mourinho's players will relish the opportunity to make a statement tomorrow. They have the extra edge that United have had for so long - and Old Trafford, the biggest stadium by far, is the stage on which to show it.