I played one opponent 4x this season, in cup first round and league. He was about 15-20% weaker (also I have well trained players, he not so much) in every game and we both played the same formations in every game. I played the same tactics in every game, don't know about him. We also had about the same players every game, he bought 1 or 2 after got knocked out of the cup.

1st game cup - I won 8-1 away (he attended, I did not)
2nd game cup - I won 4-1 home (both attended)
3rd game league - We draw 3-3 in his stadium (I attended)
4th game league - I lost 0-3 home (no one attended)

So how can it go from an 8-1 to a 0-3 when the conditions of these 4 games were pretty similar. The only factor we dont know about is his tactics. I'm just curious, I can't stop thinking about this. Is this game this random? Or do tactics actually have such a huge impact?