Newcastle United defeated Manchester United 1-0 on Sunday in the Premier League at St James' Park, condemning Ole Gunnar Solskjaer's side to a fifth game without a win.
In a match of few chances, the hosts scored the only goal after 72 minutes when debutant Matthew Longstaff drove his effort past David De Gea.
The Red Devils' poor away form continued, and despite dominating the second half, United could not find the back of the Magpies' net.
Matthew Longstaff was starting next to brother Sean Longstaff, and the 19-year-old initially had the home crowd on their feet after 28 minutes, but his shot from distance hit the crossbar.
The Red Devils struggled to create a consistent tempo, and the hosts sat behind the ball to deny Ole Gunnar Solskjaer's team any chance of a counter-attack.
The Manchester giants were poor in possession, unable to create through their midfield, and the match was a tepid affair in the first half.
United finally had their first shot on target five minutes before half-time, but Andreas Pereira's long drive was saved by goalkeeper Martin Dubravka.
Miguel Almiron should have given the Magpies a 39th-minute lead. However, Harry Maguire made a last-gasp block to deny the Paraguayan.
Solskjaer's men showed more ambition in the closing stages of the first half, and Maguire missed the best chance of the game with a poor header from six yards.
Marcus Rashford struggled throughout the first half, and Squawka Football highlighted the England international's lack of influence.
The visitors slowly turned the screw in the second half, and Mason Greenwood replaced Juan Mata, with United in the ascendancy.
Newcastle appeared fatigued and struggled in possession, but just as the away side pushed forward, the hosts broke the deadlock.
A breakaway with 18 minutes remaining saw the ball arrive at Matthew Longstaff's feet on the edge of the box, and the teenager hit the target with an impressive drive after Maguire backed off him.
The goal came against the run of play, but Solskjaer's team have made a habit of disjointed away displays.
United continued to play in Newcastle's half of the pitch, but the visitors failed to produce the quality needed to find an equaliser.
The Red Devils crashed to another defeat, and they have collected only nine points from their opening eight league games.
Both clubs return to Premier League action after the international break. Newcastle travel to Chelsea on October 19, and Manchester United face Liverpool on October 20.