Both are 5-A, speed is equalized, and Four has knowledge about Fuse’s Immortality, plus has the Anti-Flying Button with him. Both start 10 meters away from each other. The battle starts in Goiky. Planet Fuse just so happens to be right above Goiky.
As long as Planet Fuse is around, Lord Fuse is unable to die. However, Four MIGHT be able to deform Planet Fuse (Four is large planet level owing to his deforming abilities, so deforming Planet Fuse might not be too much of an issue.) Four wins by destroying planet Fuse by deforming it, then killing Lord Fuse (assuming he isn't already dead.)