Wouldn't Gaara split up the sand with Amaterasu and try to get Itachi on all side? If he has a wall of sand shielding him against Amaterasu, Gaara could split it up.
I know it wouldn't be that fast, but Itachi would need to react quickly enough. As we saw, he doesn't use Amaterasu right off the bat, he focuses his chakra first. Makes sense though since his chakra control would have to be nearly perfect to make up for his low chakra.
Itachi can use jutsus so fast that Kakashi with his sharingan can't keep up with him. Gaara is going to be in deep shit fighting Itachi because of this speed. If not for the shield around gara (second skin) i could go as far to state that Itachi is going to implant a kunai in his head from the start.
yes,it's true that gaara's defense was pretty well against sasuke's amaterasu. and it wasn't a simple amaterasu but the enton(flame element) with techniques itachi couldn't use. but in this fight they don't know each other then gaara isn't ready when itachi uses a genjutsu on him,defeating gaara. and not forgot susanoo!!!gaara's sand is nothing in front of susanoo.
Well technically, the first thing Itachi will try would be genjutsu, which means Itachi will have plenty of time to figure out a way to kill Gaara.
I don't know about Gaara snapping out just because he was cut. A Sharingan based genjutsu is different from the normal genjutsu Kurenai escaped. Orochimaru was still nearly paralyzed after having his hand sliced off and Danzo was still in Sasuke's genjutsu even after being stabbed.
I don't know for Oro that was a special stuff countering that special world of his. As for Danzou that was a MS genjutsu.
I will give this to Itachi ! Gaara is very strong and his skills are just amazing , but we are talking about Itachi for the gods sake.
Itachi is just way too much even for Gaara
It is sad to see one of the best characters go away this "soon"
Sasuke's speed in part 1 was enough to get around Gaara's sand, and Sasuke was said to have increased "dramatically" in speed and strength from part 1 to Shippuden. Itachi seemed to be at least as fast, if not more so (when healthy), than Shippuden-Sasuke, so I don't see Gaara's sand defense necessarily holding up against Itachi, either.
Also, I'm not sure I get the talk about breaking Genjutsu -- the way it was discussed in the manga, you can't really break Itachi's tsukuyomi as its entire effect happens in one second. Look at Kakashi -- he's a genius who has been shown pretty adept at handling genjutsu and he wasn't able to do anything about it.
Itachi makes me think of Minato's comments towards Bee -- he's just so much more of a true ninja in his thinking and attack style. Even if you pump up Gaara enough so that he's on equal power as Itachi, Itachi far and above has the advantage of intelligence, strategy, experience, etc over most characters in Naruto. Itachi is like Shikamaru and Sasuke's bizzare love child, and that's just too much for Gaara to handle.
Amaterasu and taijutsu are the least of Gaara's problems and some of the easier things that he can handle now. Even Susanoo could be handled if he had taken the effort to prepare the sand once he saw how tough Itachi is. The real problem is the Genjutsus. We have seen nothing from Gaara to show that he is capable of handling illusions, especially if they are of Itachi's calibre.
The only way Gaara can kill Itachi, is to make immediatly his sand sphere around him while flying far away, without making a sand eye (in order to be immune to genjutsu). Then he turns all the battlefield into sand and crush Itachi like he did against Kimmimaro. I don't remember Itachi being able to fly or to stay out of the field for a long time so even with Susano'o he'll end up dying when he won't have any chakra/life force left.
Otherwise, Gaara is screwed.
Itachi wins this. Genjutsu and Susanoo will earn him this victory.