Ruben Amorim has suggested it was a mistake to declare publicly he was managing arguably the worst team in Manchester United’s history – but insisted it would be “delusional” to mask the scale of the club’s problems.

The United head coach damaged a television during a furious rant in the dressing room after Sunday’s dismal 3-1 home defeat by Brighton and then told reporters his side were “maybe the worst team” in the club’s 147-year existence.

Amorim admitted his frustrations and emotions got the better of him and that it was an error on his part to say what he did about the team in public and get so angry in the dressing room.

But the Portuguese also doubled down on recent criticism by insisting he was not going to mislead fans into thinking United are not facing huge issues and warned he could not promise not losing his temper or speaking out in the future.

In another remarkable show of honesty, Amorim – who usually does not address his players immediately after a match – said: “I’m a young guy and sometimes I make a mistake and that’s why I don’t [usually] talk [to the players] after the game.

‘I don’t promise you I won’t do it again but I will try to improve’

“This game, I needed to talk and maybe it was a mistake and then I get more nervous and go to the [press] conference really nervous and you say things I shouldn’t say, that’s it. Sometimes I’m a young guy and I make mistakes. I don’t promise you I won’t do it again but I will try to improve.

“I understand I give you that headline and I am frustrated sometimes. Sometimes I should not say it in those terms but it is what it is and that’s it. Sometimes it’s really hard to hide the frustration in the moment.

“But the good thing is I said the same things in a different way in the dressing room five minutes before. The response was quite normal because I’m really blunt with my players.”

United have lost seven of Amorim’s 15 games in charge and face Rangers in the Europa League at Old Trafford on Thursday night having been beaten in four of their past five home matches. Marcus Rashford – who has not played for nine matches – trained with the rest of the squad on Wednesday morning but it remains to be seen whether he will be involved.

Victory against the Scottish club would represent a significant step towards securing a place in the round of 16, but Amorim admitted his team were more nervous playing at home than away and said it would be “delusional” not to accept the team’s current woes.

“I’m saying the obvious,” he said. “If you want, I can be delusional and say different things. I say it as I saw it. I said to the players and I said to you I think it’s a good thing to be really honest with you. You saw one thing, I saw one thing, and I could tell you a different thing – I can start to do it, it’s easier for me.

“But what I’m saying is that – and they know – you can understand the game, if you are in the stadium, you can understand it. So let’s face it and work on it.

‘It’s getting harder for everyone to play at Old Trafford’

“I could say different things and say, ‘no, no, it’s the same thing, we have the support of the fans’. No. We are more nervous playing at home than away. We lost four games in five, so it’s getting harder. But we can improve.

“If we don’t suffer the first goal in the fourth minute, 10th minute or 15th minute, it’s really hard to calm down the team. The first thing in my mind is, ‘They cannot score, we need to score the first one’. If we score the first one I think that will change and we will improve.

“We are really anxious, especially playing at home, we suffer goals and it’s really hard. It’s getting harder for everyone to play at Old Trafford. The way we play, we are too nervous with the ball, too nervous, really anxious.

“I’m not taking responsibility from the players. I am saying I am really, really direct in things. I’m saying in this moment we are performing really bad and our results are really bad in the moment. I’m just pointing out that I am the biggest one responsible for the performance and the results, because I am the coach.”

United have conceded first in their past five home matches, with Nottingham Forest, Newcastle and Brighton all scoring in the opening five minutes.

Harry Maguire: “We’re not mentally focused”

Harry Maguire says United need to be more switched on if they are to stop the rot of conceding early opening goals.

“Football matches are sometimes decided on fine margins and at the moment we’re not getting those small margins because we’re not mentally focused to make sure we go the whole way,” the United defender said.

“We spoke about the first goal at Old Trafford and it’s not that teams are coming to Old Trafford and opening us up. It was a 50/50 game versus Brighton which could have gone either way and we gave them a goal early on that we know we needed to stop, we spoke about it in pre-match, we have to stop giving away that first goal.

“The first goals against Forest and Bournemouth were set-plays, these aren’t things that are tactically a problem, they are things when you have to go into the game and be focused and mentally ready to go on and win football matches.”

Meanwhile, in transfer news, Napoli and Chelsea are both interested in United’s Alejandro Garnacho but Amorim refused to be drawn on the Argentina winger’s future or whether he would have money to reinvest if the player was sold this month. United are in talks with Lecce about Denmark left-back Patrick Dorgu.

“I understand the question but let’s focus on the game, I don’t want to talk about that, especially before a game,” Amorim said about transfer speculation. “Our focus is that our players are here to play. We need to improve, we need to win games to have that feeling of winning, so let’s focus on that today.”