Board Thread:Versus Debates/@comment-26636534-20170619154549/@comment-734582-20170625145659

Kakashisologod1 wrote: If that was the case sasuke wouldev had saw susano @Thekillman.But honestly, we can argue wether it was plot or not.For sasuke we know that 10000% as he was out of chakra. First off, Sasuke had a giant glowing lightning dragon above him followed by an intense flash of light. Since he didn't have his Sharingan active, he wouldn't have noticed the faint glow of say a Ribcage Susanoo in that moment, especially if Itachi timed it (or reacted to it) relatively late. Itachi doesn't need to form a susanoo in a literal microsecond to block the attack, nor for sasuke to not notice it.

Secondly, sasuke being out of chakra versus Deidara wasn't explicitly confirmed. Sasuke deactivated his Sharingan presumably to conserve chakra or because he was being cocky. It's Deidara that speculated he was out, even though his summoning of Manda clearly shows Sasuke wasn't.