In my cup I have beaten a team with 5 quality higher the past few days, twice, both home and away, never in danger of losing. In the league I faced two weak teams ( more than 10 quality lower). it was two draws, despite having good formations against them. Pretty much the same players used. So there could be something more to it than randomness.
But still...there are far more pressing matters in this game that need fixing (such as...not having screens that are too white...*cough*)