You avoid Tsukuyomi in many ways but once you've been trapped by it you can understand time distortion by being aware that you are in a genjutsu and through perfect chakra control counter the effects in your head. Tsunade is an strong-willed woman who never gives up. The way she have to get out of Tsukuyomy is easy: Just outlast enough time to understand it or release her Yin seal so that she surpasses the amount of chakra the sharingan user is using in the genjutsu, therefore making it impossible for Itachi to control her mind.
I'm just saying, it can go either way,,, but Tsunade have the best chances to get out of it. Itachi's words "every single jutsu have a weakness"
..... so, why do you Uchiha fans go against the genious Uchiha's words? Why don't you just accept it is jus another jutsu and that therefore it can be countered? ... Itachi is not the only great shinobi yo know? Not all the rest are fodders just because he has Tsukuyomi and Amaterassu. Any fight can go either way, just depends on the passion either fighter puts in.
Just keep that in mind... the fanboysm is not letting you be fair, honest and think clearly about this debates.