Arsenal failed to win any of their first three games in November but appear to be returning to form, scoring ten goals in two games.
They followed a 5-1 win against Amorim's former club Sporting in the Champions League with a 5-2 win at West Ham on Saturday.
United's Portuguese coach faced Arsenal's Mikel Arteta in the Europa League last season and his side saw off the Gunners on penalties to reach the quarterfinals.
Arsenal won the FA Cup in Arteta's first season at the helm in 2019-20 and have finished second to Manchester City in the Premier League in the last two seasons, with players such as Bukayo Saka, Martin Odegaard and William Saliba forming the core of the side.
Amorim was full of praise for the work of Arteta, who had overcome a difficult period in building his team, and stressed the importance of sticking with such a coach in difficult times.
“[He has done] “A great job,” said Amorim. “Sometimes coaches are judged solely on titles, but what he has done with Arsenal is amazing.”
“He changed the team, he bought some young people who are now a great talent in this country. I hope he has the same attitude as he does in difficult moments, because I have followed the Premier League for a long time and that is a very good quality. “In Mikel he is doing a great job.
Asked how important United's trust in him was, Amorim said: “It's always important for a coach to have that trust.”
“We have to acknowledge that Manchester United is a bit different, all the attention you need.” [journalists] We'll try to do things a little faster.
“There is tremendous attention and massive judgment here every day.”
