Genjutsu is a non factor here.
In a straight Taijutsu perspective, I would imagine Itachi as having the natural upper hand but Sasuke can take defensive measures such as
You must be registered for see links
and a streamed blade which would have Itachi on the defensive due to his inability to parry him, which could potentially harm him; I don't recall Itachi having manga intel on either of these abilities so he can very well get caught. However, I do ponder whether Itachi blitzes Sasuke at this distance since he was capable of getting behind Bee, but again, near instant defensive measures like
You must be registered for see links
to counter should suffice, with Sasuke eventually adjusting to Itachi's speed just as he did with Naruto back at VoTE. Itachi's also very proficient at clone feints but Sasuke does have
You must be registered for see links
and I can't imagine a scenario with him getting blindsided. Worst comes to worst, he gets hit but escapes with body shedding technique, allowing him to be cautious from there on it. I just feel as if Sasuke has more to his arsenal than Itachi, with wide range and versatile ration techniques which would eventually overwhelm him.
