Gorgon is that monstrous hero slayer that required the Olympians to give NPs (specially geared to defeat her) to Perseus so he guy could even stand a chance.
She has stats that places her in a different category, can buff herself with Monstrous Strength / Full Gorgon Mode, as well as possessing debuff skill / NP and a healing factor that likely allows to survive Galatine when combined with her ridiculous size and durability. She also apparently regens maryoku.
tldr; Odds are Gawain either, at best, survives until dinner or, at worst, ends up as a snack.