When I win a ranked battle, why does my rank go down instead of up?

Avinia3000

For some reason, every time I win a ranked match, my rank lowers a class etc Expert 5-Great 1. And my brother, every time he wins a battle his rank goes up way too much like Great 1 to Expert 5. And then if he loses, same with me, his rank goes down Expert 5-Great 1. Please help me.

Carter3329

That also happened to me idk why

SG_437

After Great 1 you reach expert 5 . It works like great 4321 expert 54321 veteran 54321 ultra 54321 and finally master