Itachi doesn't have much to do against Madara. Every single technique Itachi might know (Uchiha related) it's almost a fact that Madara knows it as well, plus his strength has been shown all across the series that it's actually Genjutsu (shown in his fighting style with genjutsu crows, Tsukuyomi, Izanami, etc), which I would suspect wouldn't do much good against someone of Madara's caliber, not even counting him having at least the same eyes than Itachi.
Saying that the Yata mirror would deflect any attack is the same as saying that Madara is the strongest Uchiha. Perhaps true at the time both things have been said, but we do know now that, for example, Sasuke is the strongest Uchiha and that the Yata mirror hasn't shown anything else than the fact that it can awesomely repel exploding tags and a sword hit.
Itachi doesn't stand much chances here.