Hi, I see this is a common problem starting from level 8.
Below that level I used to beat also 2 level upper teams, and I often reached the semifinal,
now I'm on level 14,and,so to change ,I went out at the qualification round (2nd).

But this may also happen in Champions league,against appearently poor teams,when you reach the playoff rounds.

This may be,because in the League there are often too many illegal teams,and you can dominate them very easily and the form of your team becomes poor.

Now I'm training my team with many friendly matches against 15 and 16 level: sometimes I win,sometimes I loose,as logical.
What's important is to maintain my team condition high,and improve abilities.

I'm expected to see a better start in Cup competition for next season.