And the tyranny steam jutsu. But gaara countered that with hearing it, and itachi's an uchiha super-prodigy who got amaterasu, so his fire and heat can counter that. Genjutsu probably wouldn't on him cause sharingan can see through it unless it'd tsukuyomi level. So all that left in the equation is the water gun and balloons jutsus which probably won't be able to penetrate the susanoo, let alone itachi's that got the yata mirror. And even if we were talking on reincarnated gengetsu, itachi can seal him with the totsuka sword. Don't get it wrong, gengetsu's super OP in my eyes, but itachi's even more with his impenetrable susanoo shield, the yata mirror, and his flaming sealing blade, the totsuka, along with the amaterasu, tsukuyomi and his amazing speed, shurikenjutsu and fire style.
