1) Uchiha (Senju only won because of superior numbers)
2) Senju
.... the strongest Senju (Hashirama) was more powerful (stated and shown) than the strongest Uchiha (Madara). The second most powerful senju (Tobirama) was more powerful (shown) than the second strongest Uchiha (Izuna).
Other than that, I don't remember implied the individual members of the Uchiha were more powerful than the individual members of the senju.
Maybe the senju had superior numbers when they won, that doesn't mean they wouldn't have won without superior numbers or would have lost.