Once the third goal went in and defeat was inevitable, the Stretford End launched into their tribute song to Michael Carrick and then turned on the people they blame for bringing humiliation on their football club.

On the Glazer family. On Sir Jim Ratcliffe. On director of football Jason Wilcox. And, finally, on the players themselves.

There is no doubt in their minds where the responsibility lies. No doubt at all that Carrick has been hung out to dry from the boardroom to the dressing-room.

But they know that one man in particular always pays the price in moments like these, and Manchester United will shortly be looking to make a third managerial appointment this year.

Carrick insisted that his lap of the pitch after the final whistle, applauding supporters and patting his heart to the Stretford End as he disappeared down the tunnel wasn't farewell, but it certainly felt like one.

The moment he was out of view, the cheers turned to boos as the players followed behind him.

So how has it come to this? How has a team that suffered just two defeats in 17 games after Carrick replaced Ruben Amorim in January lost half of their 12 matches this season and left their head coach facing the axe?

Some will say it was inevitable. That a man whose only other managerial job had ended in the sack at Championship club Middlesbrough seven months earlier should never have been in charge of Manchester United in the first place, no matter how good a player he was here or how steeped he was in the Old Trafford traditions.

They made the parallels with Ole Gunnar Solskjaer, uncanny as they are, and will look at United's horrific slump this season as vindication of those views.

United's decision to only give him a two-year contract suggested that their faith, too, was hardly unshakeable.

Certainly, Carrick needs to take his share of the blame, and he wasn't trying to duck it after the 3-0 defeat to Bournemouth left United in 16th place. He is a good man.

But he is not an inspirational leader and at times the passion and intensity missing in the team have felt like a reflection of their head coach – even more so in recent weeks when he has stood on the touchline next to adversaries such as Diego Simeone, Roberto De Zerbi and Cesc Fabregas.

On Sunday, he was frozen in a familiar pose as the misery continued, only unfolding his arms when it was time to stroke his chin.

'I don't think now sitting here is the perfect time to go through everything,' said Carrick afterwards. 'To finish third last season was a really good achievement in the circumstances to get to where we did and the amount of results that we did.

'We definitely knew we hadn't cracked it and there was a lot of work to be done, but that doesn't mean to say it should have gone this way.

'We understood where that left us and what was next; what needed to be done, how we needed to improve, and kind of where we were at as a team and as a group at that stage.'

And that is where the real problem lies. Whether he was the right man for the job, Carrick knew what was needed to take United to the next level and his employers knew it.

But the money wasn't there to make improvements this squad needs because the Glazers continue to drain money out of United, and the mismanagement under Ratcliffe has fallen woefully short of Ineos' best in class mantra. 

'Sell United and f*** off home,' chanted the United fans on Sunday.

United failed Carrick in the transfer market last summer by only spending £150million, just as Lisandro Martinez said they did in Madrid earlier this month. It wasn't by chance that the fans directed their fury at Wilcox here.

Yes, United's midfield needed work, but they also needed a striker and a left-back to provide cover for Benjamin Sesko and Luke Shaw. When both players quickly succumbed to injury at the start of the season, it felt like an act of gross negligence.

Of the midfielders brought in, Carlos Baleba wasn't able to play until October and Youri Tielemans has been so poor that he was hooked at half-time against Bournemouth. Andrey Santos is a poor imitation of Casemiro.

It has left United's squad still in need of the 'open heart surgery' interim boss Ralf Rangnick identified five years ago, a lack of quality that has undermined a succession of managers since then.  

Bournemouth have now won 3-0 on three of the last four visits to Old Trafford (the other result was 4-4). Those three defeats came under three different managers – Carrick, Amorim and Erik ten Hag – which indicates that what happened here is not an aberration and it will happen again unless there is fundamental change at United beyond sacking the manager.

Which brings us to the players. They too have let down Carrick having done enough for him in the second half of last season to pick up their bonuses for qualifying for the Champions League. 

Bruno Fernandes, in particular, has gone from PFA Player of the Year to a sulking prima donna in the space of a few months, culminating in his personal criticism of Carrick after the disastrous defeat in Como on Wednesday night.

Carrick responded by dropping his captain to the bench on Sunday and then left him stewing there as a he sent on four substitutes including teenager Shea Lacey.

It was a show of strength from Carrick, but one that may have come too late. Rather like Jose Mourinho leaving Paul Pogba on the bench during his last stand at Anfield in December 2018, it will make no difference to what happens next.

United are set to sack Carrick and then the same people at the top will bring in someone else to manage the same group of players, and the whole sorry cycle will start again. 

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