Shinji Kagawa became the first Asian player to score a treble in the Barclays Premier League before Wayne Rooney compounded the Canaries' disappointing day with an exceptional strike from range.
Yet the scoreline does not tell the whole story, for Norwich were only one down with 20 minutes remaining and still harbouring hopes of taking something from the game.
"I don't think the scoreline was a fair reflection but it shows the quality of the team they put out in the first place," said Hughton.
"They punished us when they got the spaces in that final period. They have the type of quality that can hurt you. I am really disappointed.
"Any team who comes here has to put in a real tough shift because you know they will have the majority of possession.
"The first goal was a poor one by our standards, but I think the second hurt us perhaps that bit more because we had to open up a little bit; when you do that against United, they have the quality to really hurt you."
- Sports & Recreation
- Barclays Premier League