Itachi instantly loses because he locked Sasuke into the Mangekyo Sharingan and forced him to relive the massacre of his clan, not once, but twice. You want to talk about overkill in the "I want Sasuke to hate me." department. Killing the clan was enough, but then torturing him with it twice? No Bueno.
I like Itachi, and think he had alot going for him in the redemption department, but there was no redemption for that part. That was just a straight up unnecessary dick move.