no, you're imagining one on one duels as how fights happen in the real world. It's just not.
If you had played football, or been in one real brawl you'd understand. There are just plain no rules. Noone knows what anyone is going to do. Noone can watch their own flanks or back. Noncombatants yell, scream, interfere, throw things. It will not take 1 round or half a round to be over, it will be over in a few seconds, and 9 times out of 10, noone will be significantly injured.
This is where a runner actually has the advantage - pre race adrenaline jitters seriously impair race performance so you learn to manage them perfectly. The general public can't do that. An MMA fighter might, but your advantage is they are trained to observe MMA rules. If you played football, you can run them over and be on your feet before they can react, then the whole thing's done.
But again, if you are in a bar, don't get in a fight. Not even a step-outside fight. Drunk people will fight just as unfairly against you.