Because we all know the quality of our first drafts are just stellar, I did end up fudging the ending by writing
"Blah blah fight scene where [My Villain] loses the end" but in case you missed my sarcasm, first drafts suck.
It's the truth of writing life that first drafts will not be perfect. Ever.
If you think it's perfect, you are wrong. I know, I know that's rude or offensive or something or other, but it's true. I'm not saying it's utter crap, it's the beginnings of a story.
Think of it this way:
Your story is a person. The first draft is just the person's skeleton. Revision and more drafts give it more meat. Organs, muscles, and skin come in later drafts. But don't let the skeleton draft get you down, it happens to everyone.
Here are some wonderful pictures that explain first draft writing.