Geyser spam from enemy hero - Any way to prevent it?

[Zhuangzi]

In terms of Zag-zag, I generally find on Impossible that there are about 4-5 fights on Rusty Anchor that are too difficult to do with zero losses until you have spent some time in Verona/Montero etc. I just kicked Zag-zag's ass at level 25, even though he cast Geyser four times. I play a very 'vanilla' gamestyle involving Paladins and Inquisitors for resurrection. Works well here.