Tsunade considered Jiraiya stronger than her at the time of the Pain arc. WA Tsunade has less chakra stored in her Byakugo seal than PA Tsunade. I guess it depends whether you consider WA Tsunade stronger in some other aspect.
@Ninja Of War That would just mean WA Tsunade's stronger, since she performed better feats and has scaling to put herself above Jiraiya... Or the statement was completely wrong so that she got Naruto to learn Sage Mode to defeat Pain.
She's actually stated to be the strongest Kunoichi in the village history... Which puts her above people like Kushina, and Mito who have the power to take down the Full Nine tails, so that's pretty impressive.
