He never faced Deva Path like Sage Mode Naruto (Stronger) who was defeated by Deva Path with at least 75% of it's chakra loss defeating the village.
Anyways, Itachi could solo Jiraiya, he doesn't even need Kisame's help.
Oh, and quit double-posting bro.
to the bolded part. i am going to break down a battle between them.
MS itachi
1. susanoo: as i already said jiraiaya can get out of range so offensively it wont be a problem defensively it is unbeatable but as i said itachi cant use it for long
2. amaterasu: sasuke was able to dodge this attack for a short while so sage mode jiraiya, who is a lot faster than sasuke, can dodge it as well
3. tsukuyomi: jiraiya has ma and pa on his shoulders who gather nature chakra and continually put it in to jiraiya thereby disturbing his own chakra continuously which means not just tsukuyomi but all genjutsu are useless. and the stuff about amaterasu only taking a second doesnt matter because nature chakra is continuously going in to jiraiya which will cancel tsukuyomi in immediately in under a second.
Basic itachi
4. genjutsu: as i already said useless with jiraiya in sage mode
5. taijutsu: jiraiya is by far stronger in sage mode than itachi is. furthermore itachi may be able to read jiraiya's movements but itachi wont be able to dodge since jiraiya can use frog kumite which will hit itachi
6. ninjutsu: this isnt even a contest. the jutsu that jiraiya uses non-sage mode is on par with itachi. jiraiya sage mode is even more powerful plus he can collaborate his jutsu with the toads
as you can see jiraiya wins in every category. i dont really know why you say itachi can solo jiraiya when based on what we've seen he cant beat jiraiya. MS and sharingan are not invincible. jiraiya can beat itachi, itachi said so himself.