Except Itachi can't do shit about it.
-He isn't stopping Mei from using the mist. Amaterasu's use, including charge process, takes longer than it does for Mei to use her Hidden Mist. Onoki can use a Rock Golem to block LoS from the start of the match, rendering it useless.
-Tsukuyomi is irrelevant since he isn't going to make eye contact from 100m away, especially not when Mist is up.
-If he's using any Susanoo below V3, Ay and Onoki would simply punch it away just like they did to Madara's. He can't hit them with Amaterasu because Ay is too fast, and he can't hit them with any kind of Ocular Genjutsu since he won't be following a Lightened Ay's movements let alone making eye contact. If he's using a Susanoo above V3, then Ay only needs to get Onoki to safe enough position where he can use Jinton to eradicate Susanoo.
-If they don't use the Ay Onoki combo, and go for Super Jinton, he dies since he won't be able to evade or counter with Amaterasu due to the mist, nor will he tank it.