Trying out word variations. "If you win" is ambiguous though. Do you mean survives? Do you mean killed the enemy creature? Do you mean both?

Another target creature you control fights another target creature you don't control, then put a +1/+1 counter on it.

This works if all you need is for your creature to survive. "On that feature of yours." sounds awkward in my head yet it very much clarifies which creature is getting the counter.

I knew this wasn't how it's written, but I have been thinking if i should start experimenting with word choice. The standardization of magic is something i support in theory, but emotionally i wish for a world where if the effect is obvious, the words dont need to be standardized, maybe if they flow it would be nicer.

this is not a prime example of flow, but the ability is obvious, mostly because I was unsure if a word for this already existed. Otherise would've used that.

Good point about winning, I think i'll go with if it kills because it fits the flavor better

better, less awkward sounding?

Maybe someone with intense wording knowledge could pop in here and help us out...

If you used periods and separated this ability into two consecutive sentences, it would be much easier to read.