Board Thread:Versus Debates/@comment-26958911-20151010214426/@comment-26537507-20151223190355

Itachi wins a short fight. A medium-length fight would be less one-sided but in most cases still go in Itachi's favour. The longer the fight goes on, the more it leans towards Jiraiya because he has better stamina and chakra reserves. If, at any point, he enters Sage Mode, his chances are improved.