MC you just overwhelmed him with such ease, do you still not realize that you are 100x stronger than him? you can easily beat him in a duel so you trying to stop the duel from happening doesn't make sense anymore so why do it?
"Oh dear God, this pain is making me vomit blood. Let me plot my revenge against the person who put me in this position so easily that he might as well been breathing! I'm sure he isn't able to watch my insidious plots despite showing they can and did. I'm a genius!"
@Doomer if he went to the duel and obliterated that guy he would have atracted way too much atention to himself and to lose he would need to get seriously (or seem to be) hurt, so this was actually a good way to deal with the ahole