Amorim insists United aren't struggling to the way he has the team set up to play.
"It's normal, we cannot run away from the results, and then you have the baggage from last season," the Red Devils boss told reporters at his pre-match press conference.
"Last season doesn't matter to me, in relation to the system we have already spoke about that. We had six games this season and we have lost three. And if we lost against Arsenal because of the system?
"It's your job to make the opinions. When you saw the game against (Manchester) City, was the first think that you thought when the game started was the system? I don't think you thought about the system in that moment. And Brentford.
"The way we concede goals, create chances, that is nothing to do with the system, that is my opinion. I'm not saying this team will do better in a different system, that's not my point.
"My point is if I look at the games we didn't win, the most important thing when I watched the game is not we lost because of the system. That is my opinion, then people have different opinions and that's okay."
Manchester United host Sunderland later today.