if he had the chance to use the genjutsu with ma and pa that he used againts the first 3 pains, i think he might have won. just my opinion.
He lost due to lack of intel and age,
If he was young and had intel he would have fought the six pains to get nagatos location, used a genjutsu to on the six paths so he could get away to nagato.
All in sage mode, then he would have had to fight konan, by the time he kills her, which he may not have, it took izanagi to save tobi, but jiraiya could have stayed within a toads stomach, but anyway by the time he would have killed konan the pains might have freed themselves some how.
Even then nagato still has massive chakra stores.
I would say prime Jiraiya wins with extremely high dif, and prayers.