Yes I am speculating it, and I am speculating it due to Itachi's intelligence,if he can find counter of Chikabu tensei,he will find a counter to Kamui and he has enough eye prowess and skill to put both Sakura and Kakashi in Tsukuyomi or countermy nets acting up so ill respond to this later.
@sachidinand: it isnt stated in any of your links that itachi knew about kamui, you are merely speculating that he may have.
@mellanoma: ok if he couldve used MS genjutsu he would have. Fact is you overrate tsukuyomi blindly. You think itachi wanted to waste his chakra on a genjutsu that would affect only a clone? No, itachi was duped into wasting his chakra casting an illusion on a clone, a feint which there is no reason at all why wouldnt fool him even if he had the MS. Kabuto with scolera was invincible to itachis tsukuyomi, anyone who avoids eye contact is in fact. The manga even stated that the sharingan can detect chakra, but its insight powers are inferior yo the byakugan. And as the byakugan cant tell a clone from the original, neither can itachi.
shadow clones>>eye contact genjutsus.
Sakura's punches using Susano'o..