Originally Posted by Astner

OK, maybe it's me. But I recently noticed that Sasuke was actually more powerful than Itachi during the fight. The only reason, Itachi latter gained the upper hand was because of the Magenkyo. The Amaterasu put out Sasuke's flame and burned away half his body, to which a lot of chakara must have been required to regenerate.

Here you can see that Zetsu states, that Sasuke is like an expert with a weaker tool, against Itachi, who in comparison is a nevice with a better tool. This is when Sasuke overcomes the Tsukuyomi.



So, Sasuke without the Magenkyo is still able to fight Itachi a standstill when it comes to genjutsu.

And here Sasuke and Itachi uses the same jutsu (Katon: Great Fireball) and you can clearly see that Sasuke overpowers Itachi, before he's forced to use the Amaterasu to get out of it.



It's safe to say that Itachi, without the Magenkyo would lose horribly to Sasuke.