The win at Carrow Road was made even more impressive because it was done without injured pair Robin van Persie and Wayne Rooney.
Danny Welbeck continued his good run of form in front of goal, and David De Gea made a couple of crucial saves. But David Moyes' selection made it look like one United career is on the verge of coming to an end.
Hernandez is a finisher and a very good one. His pace makes him ideal for running in behind defences, but he's not suited to holding the ball up and helping his team get a foothold further up the pitch.
As a lone front man he looked isolated in the first half against Norwich, and it wasn't until Danny Welbeck came on in the second half that he began to look dangerous.
The England striker took a fair amount of stick last season for only scoring one Premier League goal. But given a run up front in Robin van Persie's absence, he's shown he is capable of scoring goals.
His touch around John Ruddy and his finish deserved to win the game at Carrow Road. He could still do with being a little more composed in the box, but you can't argue with four goals in five games.
Norwich is a tough place to go, especially without your two front-line strikers. But United proved they have got the quality to win without either Rooney or Van Persie, which will delight David Moyes.
He will, however, hope he doesn't have to do it too many times. He shouldn't have to with Rooney set to return from a groin injury against Tottenham on New Year's Day.
The game will be remembered for Welbeck's winner, but De Gea made two saves that were just as important.
The days when the Spanish goalkeeper was a liability have long gone, and he's proving to be just as much of a match-winner as Rooney or Van Persie.
After one diving controversy too many and a string of poor performances, Young looked to be heading for the exit at United. But Moyes brought him back in, and the England winger has repaid his faith.
He scored against Stoke and West Ham and was one of United's main attacking threats at Carrow Road. It's difficult to see Moyes wanting to let him go in January now.
Moyes was scratching around for a right-back against Norwich with Rafael and Phil Jones injured and Antonio Valencia suspended.
His only options were Chris Smalling or Fabio, and he chose to reshuffle his defence, moving Smalling to right-back and bringing in Nemanja Vidic at centre-half.
Fabio is out of contract at Old Trafford at the end of the season and without a chance to impress, he looks to be on his way out.