It seems fun here but i'd luv to jion this conversation or should i say debate?
Itachi against six paths of pain is kinda crazy he's already out numbered 6-1 its only a matter of time b4 itachi gets pined down and captured.
The only way i see itachi winning is if deva path goes down or get sealed. Since ninjutsu and taijutsu won't work then genjutsu should do the trick but how? Tsukuyomi. All itachi needs is six well aimed tsukuyomi then its game over but we all knw itachi can't use more than 4 tsukuyomis without running out of chakra so it's an invalid option, agreed? A fight usually begins with both fighters staring at each other so i see one path going down from tsukuyomi and you can only aviod eye contact by focusing on itachi's feet. So pein is the answer, you are wrong when you said itachi can't use tsukuyomi if six of em came at itachi at once.
Amaterasu, we don't knw if amaterasu can be used on multiple targets at the same time, if yes then nagato should watch out for it moreover any path that get hit can't be revived since amaterasu won't go out until it reduce anythin it touches to nothing. For all we knw 2 bodies can't defend for 6 bodies.
Susanoo, i doubt shinra tensei can break susanoo and yata mirror can deflect it. But in the end i see itachi losing or a blind itachi losing. Itachi is smart, he has the ability to think fast so maybe he'll figure out the pains are just puppets so nagato will give away his position if he tries to use chibaka tensei. I'll insist on a draw till i can come up with smth.