I don't care how experienced you are, bare knuckles and grappling gloves are two different worlds.
Every now and then, I get a chance to talk to a dude who's a "hometown famous" former minor league hockey goon and current cop. He'll tell you the same shit. "Average people have no idea what it's like the next day, because you can't show it, the media doesn't wanna show it, other people don't wanna know about it and you don't want anyone knowing about it. It's not like any fighter wants their fans or enemies seeing weakness in them."
So much shit makes a random street fight different from organized sport. Shoes, clothing, the fear of going to jail, etc. The fear of going to jail and/or showing up to work with bruises/black eye. Explaining it to your child. Losing your job. (Not a problem for a GayNigger who has no job/no child.)
I don't work in construction nor do I wanna work in construction, so all that shit really makes it different. I'm sure if I had a job that didn't give two shits about my behavior or a family to face afterwards, I'd be 100% confident in physical confrontation. Only exception is my family. You fuck around with them and all bets are off. I'll go for the groin with a sharp, rusty pipe if I have to.