How on does your system work?

I lost a league match against a team that had 64% overall against my 94% overall, he did not attend the match, he had 0 fans on his stadium he had 1 defender at the back and 2 wingbacks and a missing right wing player, while i was in a 4 2 3 1 formation whit high morale, high condition 4 training sessions done and i still lost 2-1, it was like barcelona played a hungover B side team, and maybe because of that match ill end up not winning the league

Please can someone explain how the system works or is it just a dice roll everytime

its roll and dice with the engine and some of the low teams have very good players in their stats Example (250 fitnes and speed) and the grey stats very low (not important stats)

Dont worry yesterday i made a draw vs team 30% weaker and he had a red card (no mutant players).