I think that for example the Celts had superior technology to the Romans even when comparing only the metallurgy. But mostly the victory and the supremacy of the Romans had come initially from a superior political and military organization, combined with an iron discipline. Never from superior manpower, superior economy or the quality of equipment.
In the end this was a novel invention at the time(in the way how the Romans implemented it).
I think that the best example ever were Cesar's wars in Gaul. When Vercingetorix had besieged Cesar, his army was so uncontrolled and undisciplined that parts of the army, each lead by different chieftains attacked the Romans not only separately but also on different days.