Amaterasu is no problem as long it doesnยดt hit Luffy. People like Ay dodge it without trouble, so will Luffy.
Plus, he canยดt even suprised by it, because his Precognition. The only problem that exist would be Gen-Jutsu and if Itachi activates his Susanoo. I would say, as long the battle appeared in charcter, Itachi uses the old fashioned way and Gen-Jutsu GG.