My friend always has to be right?

OK so recently i've been noticing that with everything my friend says he absolutely has to be right, and if he is not he'll get angry and argue to the point of a fight to be right, even when it comes to opinions he must always be right... is this a type of mental illness or something? because i'm gonna start choosing who i really should be friends with if he just does it because he's an ***hole. Sometimes when someone can prove he is wrong about something by telling fact and having evidence about it he gets angry and has a hissy fit about it until the other person gives up then he declares himself a "winner" to a arguement he started about something he was obviously wrong about. but thats my question if there is a type of mental illness that he suffers from or if he's just immature