Inosuke is a skilled demon hunter. He can certainly hold his own against most opponents. That said, Tanjiro isn’t just any ole fighter. He’s one of the strongest Slayers in the biz. As skilled as Inosuke gets, he is never quite able to match the lead in terms of strength or speed. Tanjiro’s just a lot more powerful and in a one on one it can get pretty difficult to secure a win under those conditions. Tanjiro wins.