The hero isn't really expected to win his first encounter with the villain, at least that is what you expect in a narrative. He will lose the battle but it's part of the process that leads him to winning the war. In this movie, it was the island. I see nothing wrong with this. Is it an exaggeration, perhaps but it still makes sense to me considering it IS Superman. I don't consider it a plot hole, it's more a deux ex machina moment than anything else.