Come to the Premier League, they said to Ruben Amorim. Come to the Premier League, the toughest competition in European football. Come to the Premier League where there is never an easy game.

And so he did come. He came from Portugal where his Sporting Lisbon team used to win every week and braced himself for something much different. And then he ran into Everton at Old Trafford and maybe started to wonder what on earth all that talk had been about.

All football teams make mistakes. All players fail from time to time. Rarely like this, however. Rarely as fecklessly as this. This is the type of episode that gets managers in to trouble and at times here Everton’s Sean Dyche must have stood there and wondered why he was bothering.

Amorim’s United, given the opportunity, were ruthless and clinical and hungry. The two goals scored by Marcus Rashford and Joshua Zirkzee may well be seen to carry an importance beyond the winning of this game. Both players have been short on confidence and maybe a little love too. Zirkzee, the young Dutch forward, scored his first goals since August and also provided the pass of the game for Rashford to score the game’s third in the first minute of the second half.

That, though, was the only one of the goals Everton didn’t toss away on the back of individual carelessness.

The visiting team were impressive for half an hour. They were on the front foot and playing well and with confidence of their own. They perhaps sensed opportunity here and a hint of anxiety hung in the air at Old Trafford.

And then they tossed it all away. Jarrod Branthwaite – the young Everton defender that United would like to buy – had his fingerprints on the goals scored by Rashford and then Zirkzee in 34th and 41st minutes. Rashford scored again just after the break and then, in the 64th minute, James Tarkowski joined in the chaos, giving the ball away in his own half and opening the door wide open to Zirkzee once again.

United gobbled it all up and that will have pleased Amorim. He needs some belief to grow in these players and afternoons like this really help. A day that had started with United fans protesting at hikes in ticket prices ended with them feeling a little of how it once was to register scorelines like this on a regular basis. It is on the back of wins like this – however they come – that the mood inside a football club and inside a dressing room can start to change.

Equally, this was a most peculiar spectacle and given that Everton have to play Liverpool, Chelsea, Arsenal and Manchester City between now and Boxing Day it is a rather frightening thought as to where Dyche and his team may be by then. They face Wolves at home on Wednesday and that already feels like a game they must win.

Here, for a while, Everton were more than in the game. United were a little too easy to play through at this stage and a little too likely to cough up the ball. Old habits. Beto, Everton’s Portuguese striker, was given two chances. One was slashed wide, the other almost crept in. Over on the left side, meanwhile, young Iliam Ndiaye was a handful.

United looked unsure of themselves but then they scored and it proved the pivotal moment of the game.

The goal carried some luck as Rashford’s first time shot from a corner was deflected in by Branthwaite. Rashford had earned his fortune, though, with a powerful run down the left which had won the corner in the first place. Six minutes later United were two up.

This time Branthwaite had no excuses. Caught in possession by the increasingly impressive Amad Diallo, the defender’s error left United in overload heaven and it was Zirkzee who benefited, arriving late to convert in to an empty net from eight yards.

It was a big moment for the young Dutchman, who celebrated with an imaginary machine gun. It was Everton who had fired the bullets into their own toes, though, and suddenly the game felt very different.

United could now relax while Everton had to go chasing. United got their opponents again in the very first minute of the second half.

A long clearance from Everton goalkeeper Jordan Pickford was cleared and when Zirkzee played an absolutely sublime blind ball round the corner to Diallo, United were somehow numerically superior yet again. With Rashford making ground on his outside, it was all about the timing of the pass by Diallo and he judged it perfectly, enabling his team-mate to finish low between Pickford’s legs from an angle.

By now Everton seemed intent on self-harm and when they fell apart again to gift United a fourth goal in the 64th minute the away end started to empty.

This time the culprit was another one of Dyche’s dependables, Tarkowski. With time to make a pass inside his own half in front of the dug outs, the Everton defender delayed for a reason known only to himself. This allowed Diallo to take the ball from him and feed Zirkzee for a simple side foot finish on the far side.

United had now scored four at home in the Premier League for the first time since they beat Sheffield United back in April. There was time left for more but ultimately it was enough.

Amorim will feel he now has something with which to work. As for Dyche, he turned at the end to salute the Everton fans who had stayed behind and was greeted by the kind of gestures that only tell a manager one thing.