Why hasn't red give me a mega stone in Pokemon sun?

Question

i defeated him but he hasn't gave me one? what should I do? do I have to do something in particular? I really wanted to get that Charizardite X

Comments

You beat him after getting a 20 win streak in the Single Battle format?

---

This question has already been asked

Answer 1

According to this link you need to beat Red in the Battle Tree after you get 20 wins.