Sasuke with his speed wont outrun a large amount of sand coming at him, and with Gaara's vast improvements, he managed to keep up with Deidara's bird. Sasuke is close range fighter, meaning all of his techniques are useless to Gaara's defense. Gaara will eventually catch him via sand and crush him.
Hebi Sasuke takes this. Summoning isn't restricted, so Hawk is summoned right off the bat to avoid sand grasps. If Deidara can evade it, then Hawk - given the bird's connotations - and the fact that it easily evaded a close ranged Futon attack from Danzo is proof enough of its speed. Gaara is not one to avoid any genjutsu, as it's not his fighting style, so it's a game changer here as well.
the starting distance greatly benefits gaara. but ill make an argument for sasuke.
to cover that distance sasuke would need to summon manda for transportation.
Sasuke already breached the greatest defense gaara can use without shukaku
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gaara,having a lower speed than deidara, hebi sasuke should be able to replicate this feat
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now accomplishing this feat with gaara's flight would be difficult, but using the same technique he used with deidara
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with the combination of wings and the height of manda, sasuke show eaily be able to reach the level of gaara.
if he doesn't used his shield and third eye, he'll be vulnerable to genjutsu. if he used the shield he used against deidara and the third eye, he will lack the mibility to flea from sasuke's attack and would take damage as before.
I actually believe this attack would breach and kill gaara
