If your friend is going to fistfight a bully would you take action that might get him in trouble?

Towards the end of last semester, after school I hung around to see a soccer match a close guy friend was playing in. Towards the end a girl asked me who I thought would win the fight after the match between my friend and another player. This other kid has been haring him for ages and my friend has been really mature about handing it calmly and reporting specific incidents etc. but no action has been taken. I know well that objectively fighting is wrong but I was in a dilemma. Was I really going to do something drastic and call the school hot-line or the cops or something? Or embarr him by a girl intervening with ethical arguments about how violence solves nothing? (nothing inferior about girls but in all fairness he doesn't want one mothering him in front of the team?) So I procrastinated and did nothing and after the match I walked with the other girl to where the fight was supposed to happen. My friend and the other guy had a fight and I just watched. I froze and did nothing to alert the authorities (I called my bf and she said I should stay out of it) I would gladly have taken the punches for him if I thought it would have helped. I froze but not with fear so much as a moral dilemma. It seemed a pretty fierce fight with minor bruises and cuts on both sides.It's early days but the bully seems to have backed off. As I say I know fighting is wrong but I thought anything that would humiliate this guy or get him into trouble would be worse. He was upset that I witnessed it (which makes me think that if I had pushed through and begged him not to fight, he wouldn't have) What are you supposed to do in a situation like that? I definitely compromised my principles. I thought that in a situation like that I would have phoned every source of help and if necessary thrown myself physically in front of my friend.