Manchester United manager Ruben Amorim explained his decision to change the team's formation against Newcastle, moving from a back three to a back four with two holding midfielders. He stated the shift was necessary due to player availability and the team's current stage of development, emphasizing that tactical flexibility is crucial for growth. Amorim clarified that he is not rigidly attached to one system and can adapt when the team is performing well, aiming to build a stronger, more adaptable squad for the future.