Yet the new boss cannot have forecast it would be quite this ferocious as his team slumped to a fourth straight defeat.

Joelinton doubled Newcastle's advantage when he climbed above Lisandro Martinez

And the worry is that more dark clouds are gathering - it could get worse for the Portuguese with trips to Liverpool and then Arsenal to come next.

Defeat leaves the Red Devils perilously close to the Premier League's bottom three at the halfway stage.

So much so that after this latest disappointment Amorim conceded his side are in a relegation battle.

Asked about the threat of going down, he admitted: "That is really clear. It's one of the most difficult moments in the history of Man Utd and we have to address it with honesty."

Already this is a storm every bit as bad as the one that has put paid to the Hogmanay celebrations north of the border.

The Red Devils were simply blown away in the first half by Eddie Howe’s rampant Toon who scored twice and should have had more.

Alexander Isak scored for a sixth straight Premier League game while Joelinton scored almost an identical second 15 minutes later.

Eddie Howe’s men are in electric form right now and they fully deserved only their second league win at the Theatre of Dreams in 40 visits.

Only when Amorim took off hapless summer signing Joshua Zirkzee and replaced him with Kobbie Mainoo did the home side get any sort of handle on this game.

But by then it was too late as the damage had already been done.

The evening started with news of a return to the squad for Marcus Rashford – 18 days after his last appearance for Man Utd.

Amorim was short of options with Bruno Fernandes and Manuel Ugarte both suspended but even so the England forward was only on the bench.

And if the 27-year-old can’t get into this United side then his best days really must be behind him.

There were plenty of concerns before kick-off about the lack of pace in the team that Amorim picked and it did not take long for them to be realised.

Less than four minutes in fact.

Bruno Guimaraes sprayed a pass out to Lewis Hall on the left and the full back controlled before hanging up a lovely cross.

Isak got in between Harry Maguire and Lisandro Martinez and was somehow completely unmarked to nod the visitors ahead.

The Swede has now scored in six straight Prem games – and becomes only the second Toon player to achieve that feat.

VAR confirmed the full-back was onside and Eddie Howe’s men had another early goal – following the ones they got against Ipswich and Aston Villa.

And they clearly saw that the home side were there for the taking.

Isak ran onto Bruno’s first time pass and cut in from the right but tried to be too clever with his finish and chipped it straight into Andre Onana’s grateful hands.

But the reprieve was short-lived. Once again Newcastle had too much time in the middle to work the ball out to the left.

This time Anthony Gordon breezed past Noussair Mazrouai and crossed for Joelinton who got above Martinez and nodded into the corner.

It was almost a carbon copy of the first goal just 15 minutes later – United had simply not learned their lesson.

That’s 18 goals conceded by United in December – the most in a calendar month since 1964.

Amorim’s men were in complete disarray and Kieran Trippier had clearly done his homework – as he twice fired his corners right under the crossbar.

The Red Devils have conceded straight from a flag-kick twice in the space of a week either side of Christmas – but this time they managed to keep it out.

Isak fired an absolute rocket into the top corner of Andre Onana’s net and the home fans were relieved to see it ruled out for offside.

And then Sandro Tonali swapped passes with Gordon before shooting against the post when, frankly, it looked easier to score.

Just 33 minutes had gone when Amorim decided he had seen enough.

He hauled off summer signing Joshua Zirkzee and replaced him with Kobbie Mainoo in a bid to somehow stem the black and white flow.

The move was widely cheered by large sections of the home crowd while others booed as the £36.5 million man ran off.

It is hard to see how he comes back from this but if there is any consolation for the Dutchman, it is that any one of the United players could have come off.

Maybe it served as a wake up call for the rest of them as they could have pulled one back before the break.

A rare United attack saw Rasmus Hojlund get in down the left but he fired his shot just past the far post with Martin Dubravka beaten.

A loose pass from Fabian Schar went straight to the feet of Mainoo and he played in Casemiro but the Brazilian could not even find the target.

Newcastle had become a little sloppy – perhaps it was too easy for them. But they certainly seemed to ease off after the break.

Yet Howe can forgive them that – his team have banged in 13 goals in four straight league wins – and none conceded. A return to the Champions League looks on for them.

The home side went close again just before the hour as Diogo Dalot’s cross from the left was headed against the post by a diving Maguire.

Yet even when United needed a goal, there was no call from the bench for Rashford.