Suggested by Anonymous Isshiki Ōtsutsuki is a powerful fighter who even gave Naruto and Sasuke a run for their money. While Itachi is quite skilled and one of the most powerful fighters in the classic Naruto series, this is a level of power that his genjutsu would not be able to stop. Isshiki can even stop the Amaterasu in its tracks. Itachi may be able to come up with some plans to buy time but ultimately this is a match that Isshiki wins with brute strength. Isshiki Ōtsutsuki wins.