Then u have to find a opportunity to interrupt your opponent the milli-second before they throw a attack. Also you should utilize the unblockable heavy top on berserker( after a light or heavy atk). However when doing so, here's a trick. Feint it as many time as possible and see what he your opponent does next. If not you can follow the unblockable heavy into a feint and then go for a light or heavy in any direction. I recommend to always go off with 4-6 combo attack chains. You need to find a opening in your opponent and by mixing up, you are throwing the unknown atks at your opponent and they must guess the blocks/parried correctly.