In my opinion, Itachi lose. Here is why:
Tsunade isnt affected by Genjutsu because of Katsuya, her healing slugs can restore flow of chakra.
Tsunade can easily smash Itachi's Susanoo with "Stregth of a Thousand Men Jutsu".
Amaterasu can be easily evaded because of Tsunade sensory in Mitonic Regeneration Mode.
Is there more? lol
Tsunade isnt affected by Genjutsu because of Katsuya, her healing slugs can restore flow of chakra.
Tsunade can easily smash Itachi's Susanoo with "Stregth of a Thousand Men Jutsu".
Amaterasu can be easily evaded because of Tsunade sensory in Mitonic Regeneration Mode.
Is there more? lol