Battles

Legendary Three Ninja Vs Itachi Uchiha and Pein     
 
Legendary Three Ninja - Tsunade, Orochimaru and Jiraya.    

remember jiraiya did lose agains pain, orochimaru is scared shitless of itachi, and tsunade.....

and to people who actually says but it's two against one
 
 
no it's seven against three

I think Team Itachi wins this one.

itachi even said himself that his and kizami cant beat  jiraiya. and since pain wiped the floor with  jiraiya so easily, as well as stunade, im sure pain can solo this one.

Pein solos

@Nerx said:

" Team two Overstomp ... Magenkyou plus Shinra Tensei and the Rinnegan plus the Sharingan? "

as said by many others

Pein might solo this...Jiraiya didn't even get to experience being gravity crushed.  I guess if Pein goes all out he wins.  Chibaku Tensei and Shinra Tensei are too much for Jir/Oro and Tsunade had no chance against Pein when they confronted.

Pein had admitted that with knowledge of his bodies, Jiraiya would have been able to beat him and as sinister_noob pointed out, Itachi was hesitant to fight the Toad Sage. Tsunade's problem against Pein stemmed from the fact that she had to exhaust all of her chakra to protect and heal people from Pein's attacks (in this case much of the population of Konoha). Given the circumstances, she'd only have to protect and heal for herself, Orochi and Jiraiya in this battle. As for Orochi against Itachi, Orochi got too consumed with wanting to kill the guy without sorting out how to beat him. 
 
Itachi and Pein are not without their flaws either. Using Magenkyo Sharingan abilities takes a toll on Itachi. Using large-scale variants of his gravity attacks forces Pein to sever his connection to the five other bodies to direct his chakra to the Deva path. Also doing such attacks would leave the Deva path unusable for several minutes. Given the circumstances, I'd say the Legendary Sannin would have a shot at beating Pein and Itachi and that this battle is not a major curbstomp as folks are implying. I'll try writing up an argument in the Sannin's favor later when I have the time.

 Pein had admitted that with knowledge of his bodies, Jiraiya would have been able to beat him and as sinister_noob pointed out, Itachi was hesitant to fight the Toad Sage.
 

Yeah but that is a big precondition in this fight.  They don't have that knowledge of where the body is.  Because lets face it, Pein probably meant that IF Jiraiya could find the real body he could kill him since he is pretty vulnerable being hooked to the machine IMO.
 
Itachi running was probably due to the fact he was loyal to Konoha all the while and wanted to prevent war.  He followed Konoha's orders to kill the Uchiha clan then joined Akatsuki to spy on them...much what Jiraiya was doing.  Why would Itachi fight Jiraiya when running is the better solution...keeps them all alive.  Not saying he would beat Sage Mode Jiraiya but Itachi was also exhausted when he ran....he had no power left due to the repeated use of his eyes.