Manchester United manager Louis van Gaal could not believe the way his side started against Arsenal on Sunday.

The Red Devils found themselves three goals down inside 20 minutes at the Emirates Stadium in their eventual 3-0 defeat.

The loss saw United fall from top spot to third but it was the overall nature of the away reverse which had van Gaal scratching his head.

"I didn't expect that," he said.

"I was surprised - not performing our game plan, not the will to win. I didn't see that.

"We were top of the league so I was surprised - amazed, maybe that is a better word.

"When you give a team like Arsenal so much space to play football, then you know that you shall lose.

"And we have prepared ourselves also in that way, to play more contact but don't lose your aggression.

"It was amazing for me and I am very disappointed."

Two goals from Alexis Sanchez and one from Mesut Ozil did the damage as Arsenal ended a three-game league winning streak for United.