thank you for your answers.
so, no, i can find no other explanation for an in-form team such as mine to lose against a weaker in exactly the same conditions without apparent reasons. it cannot be anything else but a random thing.
but, the circus goes on. i still managed to finish 4th but now with same players, one new 7-star, same counter tactics my team concedes 3,5 goals on average against teams mostly weaker by 4-5 %. opponent managers are rarely watching the game. worst start ever!
i also did some testing - back arrows? forget it, even when i do that, players on that side are best opponents players.
i agree, you do need knowledge but it's not about football.