Hmmm..
Itachi knew that facing off with Jiraiya wouldn't be a wise decision from the beginning, maybe at that point in time he hasn't perfected his Susanoo as of yet and does not have the Spirit Items as well? That is why he was afraid of J-man?
At that point in time Itachi also had his illness right? I think he was not confident enough to take on the J-man due to his piss poor chakra reserves and going up against someone like J-man who has Sage Mode!? He is not going to last long in a fight.
My theory is, fanboys think that Itachi can beat J-man if he didn't have that illness (better chakra reserve) and if he completed his Susanoo with Spirit Items (just a speculation) at that point in time.
So lets talk about prime Itachi.
-He has better chakra reserves without the illness.
-He won't go blind from over usage unlike before.
-Complete Susanoo. (Speculating that he didn't have a complete Susanoo before mentioned above)
I am sure J-Man could handle Tsukuyomi and Amaterasu in some wickedly awesome way.
But how in the world is he going to break Susanoo with his arsenal?
We've seen it withstand a Kirin attack from Sasuke thats a pretty tough tech.
I am not a fanboy or anything, I would just like to know how J-man can beat Itachi's Susanoo?