Dunno... 5600 in gear is some good armor, a weapon, and quite a few potions of healing...
the outsider still has a 10 AC, but the fighter could be wearing fullplate +1. and carrying a +1 weapon, and a shield, making him twice as hard to harm as the outsider, while giving him a slight advantage to harming the outsider.
the fighter has a +6 / +2 attack now, and a 22+ AC, plus the ability to regain HP by takign a 5'step and drinking a potion.
By percentages, the fighter has a 70%/40% chance of his attack succeeding. The Outsider has a 50% / 25% / 5% chance.