Sasuke never fought Haku with the mist. Only reason she got killed was because Haku beasted on Sasuke and Naruto used his anger and went Nine tails to whoop Dat Ass.
You're right, my mistake. I'm confusing their first fight with the second. And remembering when Sasuke awakened but went down 2 seconds later.
I don't watch the anime, only the manga, and have done so for almost a decade. Kind of hard to remember some stuff from the earliest chapters!