Given Hiruzen trained Jiraiya, I'd have to go with Hiruzen, but by a very, very, very, very, very, VERY slight edge. Sage Mode Jiraiya is not one to mess with.
well we never saw hiruzen in his prime, cant say anything, its like people saying that we cant say madara in his prime could beat minato, or the 1st can beat minato. so yeah we never saw anything
Between having trained jiraya and having an unknown level of skill (if u go by stat book his prime would be l 5/5 stats) I think hiruzen even with j man starting in sage mode but that's just me