Manchester United manager Erik ten Hag admitted his side must change one key thing if they are to have any chance of winning trophies.
The Red Devils were in hot form ahead of two trips to London in the last few days, knowing victories against Crystal Palace and the Gunners could ignite a title challenge
But United could only manage a 1-1 draw at Selhurst Park after Michael Olise's stoppage time free kick rescued a point for Palace, while Eddie Nketiah scored late on at the Emirates Stadium to hand Arsenal a memorable 3-2 win in north London.
United now sit 11 points behind Arsenal having played a game more.
Speaking after Sunday's loss in north London, Ten Hag rued the 'mistakes' that allowed Mikel Arteta's side to score three goals and admitted United must address things if they want to win silverware.
"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," Ten Hag said.
‘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."
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He added: "Two games back-to-back have been really close. It's hard to accept when you lose in the last stage of the game.
"Today we have to accept it. We are not satisfied with this performance because we can do better. You start well and you have to take benefit from that situation. It can't happen that you concede like we did.
"This is one game. Last week we did very well. We kept them away from our box better and when they were in our box, we defended better."