Anthony Gordon scored a 55th-minute winner as Newcastle United outplayed and defeated Manchester United for the second time in just over a month.
But the victory came at a price as goalkeeper Nick Pope suffered what appeared to be a serious shoulder injury.
In-form Gordon tapped in Kieran Trippier's low cross at the far post to give Newcastle a richly deserved success that took them above their opponents and to within reach of the Premier League's top four.
It came 31 days after Eddie Howe's side recorded an emphatic 3-0 victory at OId Trafford in the Carabao Cup.
Howe's already injury-ravaged side should have been in front before the break as Alexander Isak's shot was deflected narrowly wide by Harry Maguire before Trippier's brilliantly struck free-kick bounced to safety off the underside of the bar.
When a goal finally came for Newcastle, there was no surprise it should come from Gordon, whose left-sided partnership with Tino Livramento had been too much for Manchester United to cope with.
Newcastle's win means they have beaten Manchester United in three consecutive games for the first time in more than a century.
Aaron Wan-Bissaka denied Newcastle a second with an inspired goalline block, only for Fabian Schar to do something similar to keep out Sergio Reguilon's effort, the nearest the visitors came to avoiding their sixth defeat of the campaign.
However, it was in trying to save that Pope was hurt, with the England man immediately signalling he could not continue.