The only goal of the game came on the hour as Yohan Cabaye found the bottom corner from the edge of the penalty area.
Despite chances for the hosts to equalise, Newcastle stood firm to pick up three memorable points.
Here, Sports Mole takes a closer look at the action at Old Trafford.
On target 4
On target 3
Was the result fair?
The home side may feel aggrieved not to have come away with a point, but there can be no denying that Newcastle were good value for their win thanks to an organised and determined display.
Man Utd's performance
This was as bad a showing from Manchester United as you are likely to see this season. There was a lack of rhythm, tempo and imagination in midfield, while the passing and link-up play was woefully below par. Robin van Persie's return should have given the champions a boost, but the striker never really threatened in and around the penalty box as United looked toothless in attack. They certainly missed the dynamism of Wayne Rooney, though it would be hard to imagine that his presence would have lifted the Red Devils from this malaise.
Alan Pardew's side showed excellent discipline in sticking to their gameplan as they fought toe to toe with their opponents on a memorable day at Old Trafford. They were solid defensively, soaking up any pressure that the hosts managed to put on them, while the midfield remained combative and aggressive throughout. Credit must also go to Loic Remy, Yoan Gouffran and Moussa Sissoko in attack as they kept giving the likes of Nemanja Vidic plenty to think about with their energy and directness.
Sports Mole's man of the match
Cheick Tiote: The Newcastle midfielder was his usual hustling self in the centre of the park, breaking up any Manchester United attacks with plenty of vigour and stamina throughout.
Manchester United had a great chance to take the lead in the first half as Javier Hernandez shrugged off the attention of a Newcastle defender before running at goal. However, the Mexican chose the wrong ball as he tried to pick out Adnan Januzaj when a simple pass to Robin van Persie would have been better.
Andre Marriner had penalty appeals for both sides to contend with but was right to wave away the protests on each occasion. Newcastle's continued aggression forced him to stop play a number of times, though he kept control of the match for the most part.
Man Utd: The Red Devils return to Champions League action on Tuesday as they welcome Shakhtar Donetsk to Old Trafford knowing that they are already safely through to the next round.
Newcastle: The Magpies continue their Premier League campaign next Saturday when they host Southampton.