Happens to me every time I battle.
The tournament is not based on team power. It’s soley based on rank.
When the boost change will happen, stuff like this will be less likely to be seen. Trying to overtake a chicken in speed would mean going full glass cannon.
It is not possible to trick matchmaking in Tournaments my friend. Its based on trophy count only. Once you gather more trophies you face higher leveled opponents. There is nothing wrong with that.