Imagine you are the coach of Victoria Plzen, you are about to play Barcelona in the Champions League. Lionel Messi is without doubt their main man - he can destroy your team, your tactics and your dreams in one lethal pass. Doesn't really matter what type of formation you play.

You decide to play a DM, whose main objective is to stick with Messi the entire match - regardless of where he goes. (I know this particular example may not be the best, as Barca have any number of players capable of playing the killer ball through defence, but I'm sure you get my point). He is on Messi everytime he gets the ball (hopefully even preventing the ball from getting to him in the first place).

I've seen in some matches a DM will stick with an AM/ST generally during a counter attack, but kind of drops back once they pass half way or wander off to the wings.

Most AFL teams generally use this as a key tactic - using one of their "run with" players to just stick on the opponent no matter where they go. Always maintaining touching distance and never giving their direct opponent an opportunity to receive the ball in space.

I know, as a fan, it's boring to employ such a tactic - but surely the idea of getting some sort of result against a dangerous opponent would make it worth it.

So, my question - why don't football teams use this strategy? Maybe there is a major flaw with this idea, which I cant think of!