Hiruzen is very powerful even in his old age he was the strongest of the kage which ohnoki, A, Yagura/MRI, and the 3rd and 4th kazekage's which says a lot and he nearly beat oro who is high kage level and 2 edo I doubt itachi would have made it out of that fight the winner and itachi is extremely insanely powerful but he wasn't mentioned god of shinobi and hiruzen also has a sealing tech which is of the highest caliber which is rds and hiruzen can use it through kage bushin so he can seal itachi with clones and dnt forget hiruzen is probably the best critical thinker and strategic mind even in this war he is breaking down juubito techs and itachi is great but hiruzen knws alot and he could avoid totsuka and we knw he cant maintain susano hell he can't maintain mangekyou that long so hiruzen has a chance