Hajime No Ippo.
It's a boxing anime, but it's done in a way that makes the fights seem like Naruto duels. There's a huge emphasis on preparing for the battle, usually the formula is that the protagonist is scheduled to go against some total OP mode giga-pro compared to himself, then there's a Rocky style training montage where he learns some new technique, and then there's the fight which too spans multiple episodes.
Earlier episodes have quite outdated looking animation, which does get better.
One of my favorite animes.