<p>Itachi wins. No doubt.
</p><p>I can't remember a single time Itachi struggled with a fight other than in his reanimation phase, and testing Sasuke's power. The closest thing to him struggling was when Jiraiya got him trapped in the toad and Itachi was like "lol, nah you ain't s**t" and dipped outta there.
</p><p>Don't forget that the show revolves around the power (and only that) of the Uchiha. If there was no Uchiha, there would be no Naruto. Literally anyone who is part of the Uchiha is hard to battle with. Do I need to go over of how powerful Madara himself was? Obito?(but to be fair, its hard to tell if he alone was pretty good because he did have Zetsu on his side) The next Uchiha on the list is Itachi.
</p><p>Gaara on the other hand has struggled many times. From Genin to Jonin, there have been a many characters that got close to Gaara before 1.) they were stopped by someone else or 2.) they decided not to FINISH HIM. He also had the one-tail and the sand, but that's part of his power so I'm not gonna use it against him.
</p><p>Btw, Itachi joined the ANBU when he was 11. Became ANBU Captain at 13.
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