Board Thread:Versus Debates/@comment-26998824-20151210004253/@comment-26537507-20151211234220

Game-only skills/techniques aren't considered canon so, as stated by a couple of others - Itachi basically has no PS. Personally I would argue against Shisui having Susanoo as well, but that's just my opinion.

Back on topic - Tobirama has fought with enough high level Uchiha to give Itachi a really hard time, but Itachi's less confrontational style of fighting (mostly genjutsu) will most probably win it for him. And as much as I hate them, the ethereal weapons would also be extremely useful, since Tobirama wouldn't be expecting them.