So I've already had a loss and a draw in the league this season. The loss (0-2) was against a team which has the same overall quality, but my players' white skill average is above 200 and opponent's was around 130. And today I drew 0-0 against 40% weaker team. Based on the white skill average, the real difference was much bigger.

I always prepare my team well, counter formation, at least a half of the team has superb morale, the other half very high, and condition cca 90+. So either the game engine has been changed, or dozens of friendlies per day (with only 2 main squad players though) had an impact on these results. But I don't think so, as I always win in those friendlies anyway.