Manga after Manga were Naruto never use Kurama He won by having more stamina that anybody else. Why do you think they call Him the number 1 Hyperactive Ninja?
4 days of running, fighting, protecting, training (before that). 4 days straight, so sleep..or rest. Until this war arc I use to think Guts from berserk had the most (kinda does from a more realistic pov but, eh). Don't forget he had so much chakra/will/stamina that he shared...with everyone ever. Then kept going.