The team was beaten 2-0 on Sunday, with Phil Foden and Erling Haaland scoring for City.
Despite the loss, Amorim remains committed to his playing style, which has yet to show significant success in the Premier League.
According to reports, Amorim is losing support from some players in the dressing room, particularly those who are unhappy with the team's formation.
Players have reportedly struggled to adapt to Amorim's system, and captain Bruno Fernandes is said to be dissatisfied with operating in a deeper midfield role.
Fernandes' concerns are likely due to United's worst start to a season in 33 years, which has put pressure on the team and its players.