naruto didnt defeat kakuzu on his own. kakuzu has 5 hearts kakashi took out 2. naruto took out 1.kakashi dlivrvered the last blow so really he kakahi took out 3. also kakashi and yamato had to save naruto.
so please dont say naruto killed kakuzu on his own because even if naruto rasen shuriken hit him kakuzu with 5 hearts kakuzu would have got up and killed naruto since he was out of breath after rasenshuriken.
naruto could not have beat kakuzu on his own