May I ask how you did this?

Grind a bit before the fight for Soul Burst. Don't really bother with the guard skills, since you will lose more HP (ver. 0.12 guard) by wasting turns. Spam Soul Burst if your HP is high enough. Defend and pop orange potions if not. Does require a bit of luck though; you want Klaire using normal attacks more often, which you may dodge with Friendship Ring.