For the first time since taking control at Manchester United David Moyes now has first-hand experience of how some teams arrive at Old Trafford with barely a flicker of belief that they can do anything but lose. Norwich were certainly obliging opponents, strangely lacking in ambition, and that helped to make this a comfortable stroll into the fifth round for the home side.
They will have enjoyed the stress-free nature of the occasion once Javier Hernández set them on their way with a 20th-minute penalty. Moyes can now reflect on three successive home wins and, by the time it was done, Norwich looked like a side that would be grateful to return to the more important business of grubbing around for points towards the bottom of the Premier League.
They had endured a miserable second half, starting off with Hernández heading in his second of the night. Phil Jones slashed a lovely volley past Mark Bunn for the third and it was starting to get embarrassing for Norwich when Fábio da Silva, a reserve left-back, scored with his first touch as a substitute to make it 4-0.
A galling night for Norwich also saw Robert Snodgrass taken off on a stretcher, having clashed heads with Rafael da Silva in one of the away side's few scoring opportunities. Snodgrass was breathing through an oxygen mask and had been fitted with a neck brace before he was taken to a waiting ambulance. There were 11 minutes of added time as a result, although he had come round by the time he left for hospital. "He was knocked out for a period of time," Chris Hughton, the Norwich manager, reported afterwards. "He's taken a whack and he will have an X-ray to check nothing is broken but we think it's concussion."
Hughton went on to complain at length about the penalty that had started the rout, describing it as "incredibly soft", and he was right, to a degree.
That, however, does not mean it was unjust when Leroy Fer did, as Hughton conceded, trip Adnan Januzaj. But it was certainly a wretched one to concede, bearing in mind Januzaj was on the byline, seemingly going nowhere, not even facing the goal and with several defenders in close proximity. The contact was minimal, though Hughton did clarify that he was not accusing Januzaj of going down too easily. It is just a pity for Norwich his impassioned little speech was about as demonstrative as they got all night.
Moyes, meanwhile, sent in his assistant, Steve Round, to assess their biggest win in the new job to date, one that will have taught them a few more things about some of the club's fringe players, not least that they have a more than capable deputy for Wayne Rooney or Robin van Persie.
The only disappointment for Hernández was that it took place on one of those nights when the Old Trafford crowd was in low volume and a lot of the usual match-goers had decided it was not worth the hassle. This increasingly seems to be Hernández's role but his ability in front of goal will always keep him in his manager's thoughts. Round made the point that there might be a way to involve all three strikers from the start.
Along the way, there were also some more tantalising reminders of Januzaj's gifts and some lovely flashes of the talent that will plainly illuminate this stadium for a long time to come. Wilfried Zaha, after an encouraging start, did not have such a productive time, on his first appearance since the Community Shield. He will be glad, however, to be involved at last, even if he was starting to look conspicuously weary by the time Rooney replaced him.
Moyes had gone with an experimental line-up – an unusual one, too, given that this was the first time Rio Ferdinand and Nemanja Vidic had ever started a League Cup match together. Norwich had eight changes of their own but the difference was they played with such little adventure. They had a considerable away following and it was difficult not to feel those fans had been short-changed.
Instead United threatened further goals before half-time and went further ahead seven minutes into the second half without having to extend themselves too greatly. Alexander Büttner might have been identified beforehand as a weak link in United's defence. He actually had a decent game and his cross for Hernández was beautifully delivered. The first attempt brought a reflex save from Bunn but the ball dropped nicely for Hernández to try again. This time he beat the Norwich goalkeeper from close range.
Januzaj was deployed in the No10 role here, albeit wearing No44, and there were plenty of examples of his ability to run with the ball and that lovely mix of balance and left-footed subtlety. Zaha flickered less frequently while, on the opposite side, Ashley Young had plenty of the ball but is still feeling his way back into his form after a long, unhappy sequence. Jones had helped Tom Cleverley to ensure United had control of midfield and his goal was reminiscent of a young Bryan Robson, taking aim from the edge of the penalty area, then letting fly and keeping a difficult shot down.
Rooney's floated pass set up Fábio da Silva to squeeze in the fourth and there were more problems for Norwich when their best player on the night, Nathan Redmond, damaged a hip and had to come off.