if we go by full strength from both characters itachi wins. he has an edo body. There is itachi from part 1, part 2, and part 3.
everyone uses part 2 itachi, the one that fought sasuke and died. i would not consider a part 3 itachi if he hadn't broke out of edo tensei and didn't make an impact on the storyline. unfortunately he did. he overrode kabuto's control and was in control of himself in the shinobi world war arc.
itachi stated if him and kisame were to fight jiraiya, they would draw. ok sure.
kabuto stated itachi was such a good liar, and never told a truth before his death. hmm..
my point is, we shouldn't decide outcomes from certain statements that are flawed. people always bring up the statement itachi said to kisame in his encounter with jiraiya disregarding itachi's true motives and the general information we're getting about him in the most recent manga's. put the pieces together and it makes perfect sense why he would say what he did..