United have used a back three since Amorim's first game in charge
Ruben Amorim has reiterated the 3-4-2-1 system Manchester United play in is not to blame for their struggles and indicated he would only be open to changing formations once the players have mastered the current one.
United have won eight of their 34 domestic matches with Amorim in charge and the [League Cup](https://www.manchestereveningnews.co.uk/all-about/football-league-cup) elimination by fourth-tier Grimsby Town was a new nadir in the Portuguese's ten-month reign.
Amorim was questioned on the formation in the aftermath of the 12-11 penalty shootout defeat at Blundell Park yet defended his principles. At his pre-match press conference for the visit of Burnley, Amorim revealed that United's football leadership members asked him whether he would play with a back four.
The Portuguese revealed that he spent all of his playing career with Belenenses, Benfica, Braga and Al Wakrah playing in back-four formations and the only one he did not operate in was in a back three.
"Guys, if I feel that it's best to change... I played all my life in the 4-4-2, 4-3-3. The only system that I didn't play one minute: 3-4-3," Amorim said. "I just have one idea that we need to be so good in this way of playing, then we are going to adapt.
"It's like some coaches have a mentality that I'm going to put this system, and then I'm going to change. What I'm thinking is that we have one system that is going to adapt to different systems, and then when everyone is doing this with his eyes shut, I'm going to change a lot of things.
"You cannot tell me that we are always with five defenders. You cannot tell me that we are always with four defenders. You cannot tell me that we are always with three defenders. I'm just trying to coach my players with the idea that I have.
"And I said that many times, this is the fun part. If it's just to win the game or to play in the 4-3-3, I was not here. They asked me before I arrived here, can you play this system? I will say, I will do my system no matter what. If it's okay for you, it's okay.
"And then in the future, I could change. I could wake up in one morning and say, I understand that for my idea of football, it's better to change right away.
"I just want to win. But if I'm going to change because something is not working and I don't believe, players will understand. This guy is telling you one thing, he's not believing in the other thing.
"So it's not about the system. We lost against Grimsby about the system? In the first half, I didn't know the system of the team!
"So, guys, it’s not the system."