To completely avoid the stun, you can also build high critical rate, use moves with increased critical, and/or build stun resist.
Another option is to use a defensive fighter that can survive a stun. Examples: Val with ICU, RE.
Personally, I just use two or three strong fighters knowing that one might die to stun, and hopefully the other can pick up the rest. This prize fight is definitely one of the tougher ones and not one that is easy to carry weaker for experience.