Board Thread:Versus Debates/@comment-5936871-20160126112547/@comment-1872728-20160128103723

Rinnegan is not immune to genjutsu. Sasuke is immune to IT because his Susanoo is immune to IT, and that his Susanoo is upgraded with his Rinnegan. So yes, Sasuke will be vulnerable to IT without Rinnegan, but no he isn't immune to IT by purely using Rinnegan and without the Susanoo.

Back to the thread: Itachi could win. Even if Nagato is out of his range of vision, or that the Preta Path is able to absorb genjutsu, Itachi can still cast a genjutsu to one of his summonings, and since they all have linked vision, Nagato will also be affected by the genjutsu. If that's how it works. Amaterasu and Susanoo (Sword of Totsuka, Yata Mirror etc.) is useless. Izanagi is defensive, and Izanami only works if the target used some reviving jutsu (I think), and I doubt Nagato would need to use reviving jutsu.