In England/ the rest of the UK, there are a number of words for it, such as: Supporter- this is the main one if you love the football club and you know all the players and you watch every game etc. Follower- usually used for a team that you might have supported before but not any more or a family member supports them so you make more effort to see how the team is doing. Fan- this is more of a loose association, perhaps you like the way the team play football for example but you haven't been brought up supporting them. These are mainly for football. I was just guessing because you mentioned man utd. For any other sport it is fine to use any of them. P.S. some groups of supporters have their own name. For example, the supporters who travel to watch Scotland play are called the tartan army. Hope this helps!

I would say a 'fan'. As in they are a fan of that soccer team.

Fan of ...... (any team) , maybe :)