I need help with Zalmarath boss act2

He does this annoying dagger swipe animation = 1-shot.

Here is there thing. Animation is so bad it sometimes doesn't hit my character. If I roll I don't know if it's too early or too late.

All rest attacks of him are no problem. It's only dagger swipe crap.



Edit: Just killed it. Secret was being constantly on meelee range, never go ranged because swipe is just broken animation.