itachi took out the summons when nagato wasnt paying any attention to him and itachi wasnt even in the fight at that point. itachi cant replicate what he did if its a 1 on 1 and nagato is paying full attention to itachi.
itachi gets ended by chibaku tensei.
As much as I enjoy reading new posts, I really wish people will stop raising the same point over and over again after I've already addressed them in several of my previous replies.
Nagato relies on SHARED FIELD OF VISION for his combat responsiveness, NOT STARING AT HIS OPPONENTS. For nagato fans I dont understand why you would downgrade his godly sensing ability here. Nagato/Pain often doesnt even look at their opponents when attacking them, as is the case where Nagato grabbed Bee with Asura's path.
The notion that nagato was "too busy with naruto and bee" to notice itachi was in the fight at first is PREPOSTEROUS, especially when the accusation comes from people seemingly rooting for nagato.... read chapter 550, kabuto/nagato knew itachi was on the battlefield from the start, and common sense says he's been tracking his movements from the start. Itachi didn't "steathily run behind his back to stab his pets' eyes", he disabled his shared vision WHEN NAGATO'S PERFECT SHARED FIELD OF VISION WAS STILL "ON", by using his superb skill to find ALL THE BLIND SPOTS with his shurikens.
When you think carefully on what happened, what defeated nagato was not even Susanoo's sword, for Bee has sealing jutsu too (even sand fodder's sealing would work the same way). What took down Nagato's perfect sensing ability, thus breaking through his perfect defenses, are plain, old shurikens, in the hand of a master. Now if that isn't a text book case of "pebble beating kunai" zetsu spoke of, I don't know what is.
It's true that Itachi couldn't have destroyed Chibaku Tensei on his own, but the point here in the manga is that if he didnt have to save naruto and bee, Nagato would be sealed BEFORE he even used CT.