Itachi wins low-difficulty.
In that situation, Jiraiya had locational advantage, so it was an ideal area to cast that jutsu. In this scenario, it's an open field and Itachi's more likely to feint Jiraiya here than the other way around. Jiraiya may have more versatility in ninjutsu, but it's really a non-factor as Itachi's faster hand seals and his perceptive ability to effortlessly read seals allows him to counter Jiraiya's ninjutsu.
And Summons are lol-countered by Genjutsu or Itachi's Big Crow, so they're insignificant in this match.
And Yomi Numa GG? His best feat was performing it against Human Path and Animal Path who had no viable counters against Jiraiya's main form of ninjutsu which is his Katon. Itachi has feats of countering his Katon and has Precognition and the speed and reflexes required to fend off a far Superior Sage. The fact that Jiraiya can easily Yomi Numa GG here while in Base is laughable esp. when we take into consideration that Itachi can easily read his seals and counter with Shuriken-ninjutsu or any form of Ninjutsu far quicker than Jiraiya can ever hope to complete his seals here.