Board Thread:Naruto Discussions/@comment-33953813-20171222191100

I understand that B could have passed in the waterfall exam but in the internal battle with the eight tails he must have had to defeat him. And we all know that B had control over him from a very young age.

We saw how hard it was for Naruto get control over the nine tails. He had all this to get control over the nine tails:

1) Help from eight tails

2)Sage mode

3)Kushina's chakra chains

But B was just a child back then. I understand eight tails is weaker than the nine tails but still I find it hard to believe that a child could defeat the eight tails.

This isn't property explained by Kishimoto. B never actually told Naruto how he fought the eight tails. 