Madara used propably Rinbo Hengoku to bind Sasuke, yes. However, Tobirama got just stabbed with Kokushin and lost because of that the ability to forge chakra and it limited also his movements. Tobirama got simply owned, like Sasuke and Naruto too.
The power of the Rinnegan wasn't needed for that.
Yes, The young Madara didn't have Kokushin, but he was still far stronger than Tobirama. Only Hashirama could ever compete with Madara.
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Kokushin is obvious a Jutsu, which base upon the YYR(Yin-Yang-Release=Onmyōton). I'm sure he mastered that because of Hashiramas DNA(physical energy) and his own power(spiritual energy). Yin/Yang
But the Rinnegan itself doesn't have to do with that, as I have said it before.