danzo wins for the same reason shisui beat itachi via kotoamatsukami. The strongest genjutsu ever that As far as we know cant be blocked and works on everyone. however if you want to not count that danzo still takes it. Itachi's problem is stamina, something danzo has infinetly more of, having hashi cells, 12 lives and the op senju healing because of his arm. danzo has knowledge of everything itachi had in his arsenal and had an izanagi to counter it too, and itachi doesn't have the stamina to use 12 amaterasu in a row (assuming they all even make contact with danzo) plus all it takes is danzo to touch you once and you get sealed in place (danzo touched sasuke's neck once and placed a powerful seal on him which paralyzed him) and itachi doesn't have the "power of hate" to ge tout of it. and to top this all off the only form of itachi we know is sick and going blind so i really can't see him winning. itachi is strong but danzo holding back with heavy plot armor still pushed sasuke to his limits and that's after excessive susanoo and some amaterasu, something itachi can't throw out lightly.

EDIT: also izanami wont work on danzo because danzo is completely okay with who he is.