ok, i beat this quite easily.
first, steal the hi-potions off the annoying guado guards, then cast protect on your party, which u should have (if not train until u get it)
use auron and his power break attack which lowers the damage he does.
Kill the guards, w)hich should be easy, then u should be ok.
hope this helps
(also cast haste/ga and if it works slow/ga on him