Manchester United manager Erik ten Hag has admitted that he needs to change the "attitude" of his side following their "unacceptable" derby defeat to Manchester City this afternoon.
The Red Devils were blown away by their local rivals in the first half at the Etihad Stadium, going into the break 4-0 down courtesy of two goals apiece for Erling Braut Haaland and Phil Foden.
It was the second time already this season that Man United have shipped four unanswered goals in the first half of a Premier League game, having also done so against Brentford.
There was more to shout about for the visitors after the break, outscoring their opponents 3-2 in the second half, but they still slumped to a chastening 6-3 hammering which saw both Haaland and Foden help themselves to hat-tricks.
Ten Hag admitted that he was "surprised" by his side's performance after they had recovered from defeats in their opening two games of the season to win four league games on the bounce, including victories over Liverpool and leaders Arsenal.
The Dutchman put the display down to a "lack of belief" and stressed the importance of learning from the mistakes they made at the Etihad.
"It was a lack of belief. I'm surprised why we didn't bring that on the pitch. I have seen a different team, a different spirit and a different fight. We didn't have convincement. We were not brave in possession," he told Sky Sports News.
"It is always difficult to find out. The players know they can do better. If you don't fight then you have a problem against a team like Manchester City.
"This is definitely different [to Brentford]. We didn't run there. We wanted to today but didn't follow the principles. It was a lack of belief. I will show the team that we could have been front-footed.
"We win the ball then give it away for the first goal. We take wrong decisions in the transition afterwards. We don't follow the rules so we are undisciplined. It cannot happen. It is unacceptable.
"It is a process. It is one game. Maybe against other teams the problems would not come but against Manchester City they will. I want to change the head and the attitude from the team. There was a reaction in the second half. We were more brave and scored three goals. Only from mistakes you learn."
Ten Hag added to BBC Sport: "In this moment I can't think about positives. We let our fans down, we let ourselves down and we're hugely disappointed."
The result leaves Man United sixth in the Premier League table, now eight points behind Man City and nine adrift of pace-setters Arsenal. body check tags ::