Spoilers In The Way”. (Adult) Uchiha Sasuke * Can use all five basic Nature Transformation as well as Yin Release. His Fire Release prowess is strong enough to easily disperse most Water Release technique. read more
I am going to assume that you are talking about a MS sasuke vs MS itachi. Well, in all honesty, i believe it can go either way. Sasuke could win. Itachi could win. I know some people believe itachi would win just because of the fact that his susanoo have the Totsuka Blade and Yata mirror. read more
But Itachi wasn't entirely trying, wanted to die by Sasuke's hand, AND was nearly dead from disease. All that, and Sasuke was still exhausted at the end of the fight. So yeah, clearly Itachi would win. read more