Manchester United legend Bryan Robson has argued that Ruben Amorim should be given as long as three years despite his woeful start to his Old Trafford tenure.

The beleaguered Premier League boss arrived in a hail of promise in November last year, but since his move from Sporting Lisbon, Amorim has been unable to improve the struggling side.

The Red Devils ended their season in 15th place in the league standings, and missed out on their last chance for European competition after losing the Europa League final to domestic rivals Tottenham.

After a complete pre-season and a £214million transfer window, there was some hope that Amorim would finally be able to get off on the right foot.

But since the Premier League returned in August, United have won just one match - against newly promoted Burnley - and suffered an unedifying Carabao Cup exit at the hand of League Two minnows Grimsby Town.

While some former club stars have even gone as far as suggesting who might replace the Portuguese head coach, Robson was insisted that those in the Old Trafford dugout should be given time to adjust to the pressures of managing the Premier League behemoth.

Ruben Amorim has been under fire over his chaotic start to the season at Manchester United

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'We have changed managers that many times (since 2013),' Robson told Telegraph Sport. 'I feel you have to stick and say, 'No, we are not sacking the manager. We are not blaming'.

'When you have a little bit of money and the club are going to allow you to change your squad, you need three years to get the team right.

'For me three years at Manchester United should be enough. Look at the money we spend. It's up to you to go around the world and get top players who are going to improve you.'

Amorim has had ample investment over the summer to build a side more suited to his vision of 3-4-3 football.

But as Robson would have it, some of those being recruited by Man United over the last handful of transfer windows have been lacking in league experience.

United raided Premier League rivals Brentford and Wolves to sign Bryan Mbeumo and Matheus Cunha respectively, but have otherwise looked to other European leagues for top signings including Benjamin Sesko - formerly of RB Leipzig - and ex-Lecce defender Patrick Dorgu.

'The other thing I think we went away from is getting good experienced Premier League players,' Robson continued. 'So when they get to 28 you bring them on board if you can. There have been loads of players who have left clubs.

'I think five years ago, some of the players we bought were just not good enough to be Manchester United players. It's an accumulation of that.

'When I was in management, I believed that if you bought average players you got an average team.'

Robson is a frequent presence in the stands watching Man United alongside decorated former manager Sir Alex Ferguson

Amorim has been bullish about his determination to stick to his tactical philosophy - despite the defeats

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Ahead of facing off with Chelsea on Saturday afternoon, Amorim was forced to confront that his side have had the club's worst start in 33 years.

But the 40-year-old - who held meetings with co-owner Sir Jim Ratcliffe on Thursday afternoon amid the punishing start - remained bullish about his faltering philosophy.

'No, no, no,' Amorim said on Friday when asked about if he would consider a tactical shift. 'No one. Not even the Pope will change (me).

'This is my job. This is my responsibility. This is my life. So, I will not change that,' he said.

'If I'm a player and I have a coach that, with a lot of pressure, is saying 'you need to change the system' and I'm going to change, in this moment they will look at me in a different way.

'There will be an evolution, but we need to make all the good steps. I'm doing things my way.'

Man United legend insists Amorim deserves 'THREE YEARS'