God from preacher goes and sits on the Throne of Eternity then summons SOK.
That's basically his best combat feat. If no help is allowed, the god from Preacher doesn't really do all that much himself. Off of his throne he's shown to be more powerful than angels and men, but not the Saint of Killers. He's shown to be able to perform some reality warping, like bringing Tulip back to life, guaranteeing that Jesse and Cassidy both survive the final showdown "no matter what" and even shielding certain individuals from the effects of the Genesis force. None of this really tells us what he could do against another being of his type.