Cruel Izaro too hard?

After leveling into Merciless act 2, I decided I would go back and do the cruel lab as I was over leveled by more than 10 levels. I then spent the next almost three hours without completing it even once. Quite literally all of Izaro's attacks, other than his auto attack, that hit me one shot me for over 2K damage, through my defenses. The labs are already rather tedious to run without having to do it 7 times over and still not getting it done.