United have scored only nine Premier League goals in eight games, four of them coming in a 4-0 win on day one against Chelsea.
Newcastle United's Matthew Longstaff enjoyed a dream Premier League debut by scoring a late winner as his side beat visitors Manchester United 1-0 to move out of the bottom three on Sunday.
The 19-year-old, playing in midfield alongside his older brother Sean, had clipped the bar with a dipping first-half effort but made no mistake as he beat goalkeeper David de Gea with a sweetly-struck low drive after 72 minutes.
While the there was some much-needed joy on Tyneside for Newcastle's fans, who celebrated only a second league win of the season, another lacklustre display by United left Ole Gunnar Solskjaer's side in the bottom half of the table.
United have scored only nine Premier League goals in eight games, four of them coming in a 4-0 win on day one against Chelsea, and again they looked bereft of attacking spark.
Their best chance saw defender Harry Maguire head wastefully wide from a corner on the stroke of halftime.
The 20-time English champions will enter the international break in 12th spot, two points above the relegation zone and 15 behind leaders Liverpool who they host in a fortnight.
Newcastle are a point behind United in 16th spot.
It was Steve Bruce's best day since replacing the popular Rafa Benitez as he claimed a first win as manager over his old club at the 23rd attempt on his 400th match in charge of a Premier League club. However, the day belonged to Longstaff.
"I'm a bit in awe really," a beaming Longstaff said alongside his proud brother. "Last night I was dreaming about this but never thought it would happen.
"I found out yesterday that I was playing, the butterflies started yesterday but I've been looking forward to it ever since.
"To get the goal in front of the Gallowgate makes it extra special."
His brother added: "He's been the best player in training. He was a breath of fresh air. I couldn't be prouder of him."
Newcastle, thrashed 5-0 at Leicester City last week, were well-organised at the back and looked the more threatening side in a dreary first half.
After 28 minutes the livewire Allan Saint-Maximin set up Longstaff with a short pass and the teenager's dipping effort beat De Gea but not the woodwork.
Sean Longstaff then played in Miguel Almiron with a quarterback-type delivery but the Paraguayan delayed his shot too long and his effort was blocked by Maguire.
Solskjaer's side had plenty of possession but United's England striker Marcus Rashford was anonymous and touched the ball only nine times before the interval.
The visitors should have scored though when Maguire was unmarked from a corner but his header was mistimed and went wide.
Former Toon Army fan favourite Andy Carroll, enjoying a return to his hometown club, came off the bench for Newcastle in the 52nd minute but the supporters found a new hero.
When Saint-Maximin teased the United defence again it allowed Longstaff to advance into space on the edge of the area and when the ball was played back to him he only had one thought as he lashed his shot low into the corner.