It was a moment I will never forget. He went past me, I stuck out my leg and Lionel Messi went over. This was at Old Trafford in 2008 in the second leg of our Champions League semi-final against Barcelona and, with the score 1-0 to us, I had fouled him in our area.

When I think about our win over Barcelona in that game, on our way to the second Champions League title of the Sir Alex Ferguson era, I always remember that tackle. Yes, I scored the only goal of the tie, and it was one of my better ones. But I will never forget that couple of seconds when the best footballer in the world deceived me into fouling him and I waited for the world to fall in.

It should have been a penalty to Barcelona, and an away goal would have won them the tie. But for some reason the referee didn’t give it, the game moved on and even Messi did not make much of a fuss. The relief was overwhelming for a few moments – and then I was back into the game.

He got his own back in the end. I faced Messi four times in my career, twice over the two legs in 2008 and then, as a substitute, in the Champions League finals of 2009 and 2011, when Barcelona beat us comfortably both times. Messi is back in Manchester next week, to face Manchester City again in the Champions League round of 16, and it is never a bad day when you can watch one of the best footballers ever pull on a pair of boots.

There have been so many superlatives to describe Messi’s career that you find yourself just adding to the pile of words about him. So these are some of the little things that you learn when you play against the man himself which you might not see on the television. First off, he never speaks on the pitch. In fact, I don’t think I ever heard him say a word. Second, you won’t believe how strong he is for a little man.

I am not ashamed to admit that in the games against Barcelona I spent a lot of the time just hoping he would take up positions as far away from me as possible.

Elusive is the word that immediately springs to mind when I think about Messi’s style of play. You think you have an eye on him and then – blink – he has gone, only to reappear somewhere else in space, with the ball. When you try to face up to him and make a tackle you know what it is he is going to do with the ball. The problem is staying with him.

He avoids the highs and lows of football. You rarely see him go over the top in a goal celebration, just as he never gets too downhearted. That’s a quality I think that I shared when I was a player. The game changes so quickly and you have to get yourself in a position mentally where you can deal with whatever is thrown at you.

I have never seen a United performance with such a high level of concentration as when we beat Barcelona at Old Trafford. For every second of that game, and the first leg at the Nou Camp, we had to be aware of our positioning, of the dangers they posed and our shape as a team as a whole. We spent the whole week working on it with Sir Alex and the staff. We knew exactly what we should be doing at all times. Then we had to do it over two games.

The two finals were different. In preparation, we thought less about them and more about what we could do. We had Cristiano Ronaldo and Wayne Rooney for the first one in Rome and we believed we could hurt them. Perhaps we underestimated them.

When you prepare to play Barcelona you go through the usual weaknesses. Gerard Pique lacks a bit of pace. Javier Mascherano is not really a centre-half (the position he played in 2011). But you can only exploit those weaknesses when you have the ball. We had 37 per cent possession in the 2011 game and we were used to having a lot more.

There was never any specific plan to deal with Messi, simply that whoever was nearest picked him up. Rio Ferdinand had two great games against him in 2008 but no one keeps him quiet every time. As a finisher, there are few players as composed as Messi. When you can score as many different kinds of goal as he can, you have every reason to be confident.

People say that I played under pressure, as a Manchester boy at United where we were expected to win every week. But it is nothing compared to the pressure Messi is under, and Cristiano too. They go a game without scoring a goal and people want to know why. Not just fans either but former players who should know better. We expect it of them now and that they keep doing it is incredible.

Messi is as famous as any footballer has ever been and yet, when it comes down to it, we don’t know much about him. I read that he is a family man, and likes to walk his dogs, but beyond that he’s a mystery really. I like that. Especially these days, when people’s feelings about every issue are there to be read on Twitter or wherever. Keep something of yourself back. It is a strength.

I am looking forward to seeing him play at the Etihad Stadium on Tuesday and if City want a result then their concentration and focus will have to be as good as it has ever been to make sure they are in the right place at the right time for 90 minutes. It only takes a second for that little No 10 to trick you into doing something daft. And you can’t always rely on the ref not to see it.

Villa don’t seem to have enough leaders in their squad

There is still a prestige to managing Aston Villa and for Tim Sherwood this is a great job. The question that would worry me in that position would be whether he has the players he needs in the long term.

Villa’s squad has enough quality to stay up. My problem with it is that I don’t see too many leaders among those players. Rather, there seem to be a lot in the comfort zone, playing for a big club but not really making a difference. I imagine Tim has the kind of personality that will not tolerate anyone coasting along.

Some of the signings last summer felt like they were made by a club that had run out of options. Philippe Senderos has not played a minute since November, having first been injured on international duty. Joe Cole has started three league matches all season. As a manager you live and die by your recruitment and you have to wonder about those two signings.

The way that teams turn around difficult situations is by being prepared to criticise one another, and have some difficult conversations. To do that you need to have a spirit among the players, and a few characters who are prepared to lead the way. And failing that, it has to come from the manager.