Remember:
Just before Jiraiya left to combat Nagato he and Tsunade were speaking in private. She assured him that all he needed to do was send for help and that she would come to his aid and they would face the danger together. Jiraiya declined.
We know how the battle concluded. Even without knowledge of the Rinnegan's long-forgotten abilities and Nagato's personal jutsus, Jiraiya was capable of defeating three of his Six Paths. However, after being ambushed, he was unable to overcome all six.
Now we speculate. Enter Tsunade; if Jiraiya had planned to call for help, the moment he lost his arm would have surely been it. With a one-armed Jiraiya by her side, could Nagato have been defeated before ever invading Konoha?