Manchester United put the game with the Gunners back on level terms in the second 45 and looked content to sit back and secure a draw.
However, their players defended poorly and became erratic with their passing.
This allowed Arsenal to capitalise and secure a late winner.
Following the game, Erik ten Hag stated that Manchester United need to change their mentality if they want to win trophies – something they have not done since the 2016/17 season:
“Maybe that will come in the next couple of hours, that we will realise we are in a good position, realise we are in a good development and a good process,” said Ten Hag.
“But in this moment I am annoyed and I also told the players: ‘If you want to win trophies, titles, you have to change our mentality, because it’s not possible that you are in a top game making three such big mistakes where you concede’.
“Then especially the last goal, you have to feel the game. At that point, a point was the maximum.
“Then you have to take the point and you can’t give such a goal away like we did. And on top level, you can’t win trophies. It was like a pack of cards with the goals we concede.
“Two starting with a corner and then obviously we make mistakes, we didn’t show the discipline in the rules we have there. Then you concede goals.”
Asked how he changes the mentality, Ten Hag said: “With coaching we change that.
“Already we have seen how the mentality from the players has changed over the last couple of months. But we also have to notice today that we still have a way to go to be on top level.”