United announced on Sunday that Ashworth will leave Old Trafford after only 159 days in the post following his move from Newcastle.
The 53-year-old was expected to spearhead an overhaul of United's underachieving team, alongside new boss Amorim, who was hired from Sporting Lisbon in November to replace the sacked Erik ten Hag.
Instead Ashworth's departure raises fresh questions about United's future under co-owner Jim Ratcliffe.
Amorim's side are languishing in 13th place in the Premier League after last weekend's defeat against Nottingham Forest.
Ahead of Thursday's Europa League game at Viktoria Plzen, Amorim faced the media for the first time since Ashworth's exit and conceded it was hardly ideal.
"The first thing I want to say is that since the first day I felt great support from the ownership," he said.
"From Omar (Berrada, chief executive), from Dan also, from Jason (Wilcox, technical director).
"Dan was part of that, and I really felt support from Dan also. But this is football and sometimes these things happen. It happens with players, with coaches.
"I know that it's not the best situation but the important thing is we continue in our way. The path is really clear for everybody and I think this can happen in football."
Asked if he is concerned that United were more unstable than when he first arrived a month ago, Amorim said: "I don't think so.
"Like I said, I've felt since day one the support from everybody, so one person leaving don't change nothing.
"Of course, it's a bad situation, like I said, because we are talking about a human being, a professional, that supports us as a team.
"But I think the most important thing is that your vision is really clear and that vision don't change if only one person leaves."
United are looking to bounce back from successive defeats against Arsenal and Nottingham Forest.
Those losses have fuelled talk that Amorim needs to make major signings in the January transfer window.
But Amorim said: "I'm really focused on to see my players and to understand my players. I think that is one of the problems of the clubs.
"Every detail counts and we have to be very clear first in the profiles, arrange all the process and then go to that phase of buying and selling players.
"We have to improve as a team, we have to arrange a lot of things in our club before thinking just in buying or selling players."
United are looking to secure a first away win under Amorim and the club's first European victory on the road since March 2023.
Amorim's men are level on nine points with Viktoria in the new-look Europa League standings as they bid to secure a top-eight finish.
"For some teams it is nothing. For us it is really, really important," Amorim said.
© 2024 AFP