Well, first of all, The Fight is a mini game, what we players play and win.
So if We win and then we get a scripted event where we actually lose just because of story it would not sit well with the audience as it not sit well in the previous cases.
We already had 3 scripted event, when even if we beat the mini game we technically didn't win in the sense of Story
we don't need another one.
Vinny doesn't have to be some MMA fighter to take him seriously, or be dangerous.
and as I said, if he beat MC, it would be the opposite reaction. He would not come out as some badass foe , but a stupid game decision.