Hiten:

Naruto will never beat itachi. He won't be strong enough to pull that off till near the end of the series, or if he does become strong enough at some point, he won't get the opportunity to kill him, cuz Sasuke's gonna do it. But that's ok, we'll then get to see the Naruto/Sasuke rematch that matters.

And Naruto most certainly did grow mentally. In his previous fights, he never thought about the weakness inherent to an enemy's abilities. This time, he did. Plus, there was that kage bunshin trade off "game" he played with Kakashi at the beginning of the fight, which ended in a stalemate. Seeing as Naruto wasn't made to look like an idiot during the fight, he came up with a strategy to take advantage of a disadvantage in his opponents ability (which he never did before), and did all this using only his trusty kage bunshin, I'd say he grew mentally. Quite a bit.