Louis van Gaal
van Gaal left frustrated with United's second consecutive defeat.Getty

Manchester United manager Louis van Gaal has pinpointed his side's lack of motivation, aggression and inspiration as the most disappointing aspects of their humiliating 3-0 defeat to Everton.

Goals from James McCarthy, Seamus Coleman and Kevin Mirallas sealed victory for Roberto Martinez's side on Sunday 26 April on an afternoon where United also lost Wayne Rooney to injury.

Van Gaal slammed the performance and admitted the defeat offered 'light' to Liverpool in their bid to close the gap on United and beat them to Champions League qualification.

And the Dutchman also admitted there were early warning signs that something was not right as his side were given a firm reality check on Merseyside.

"I think it was the most disappointing performance because it is the first time that I have seen our motivation, inspiration and aggression was not as high as the opponent," van Gaal said in his post-match press conference.

"In sport you shall always be compared to your opponent and that was the reason. I had already the feeling and my colleagues Ryan Giggs and Albert [Stuivenberg] had the feeling because the warm-up was not so good as usual.

"You hope you can recover and stimulate your players by saying something before the game but by then it is too late. You have to prepare the match two or three days before. Everton did that and they have won because of that."

United, currently fourth in the league, have a seven point lead over arch-rivals Liverpool but that gap could be reduced to single point by the time United next play.

Liverpool have a game in hand away to Hull City on Tuesday before they host Queens Park Rangers on Saturday. United welcome West Bromwich Albion to Old Trafford in Saturday's evening kick off.

"We cannot explain it [the defeat to Everton] because it is dependable on a lot of factors and one of the factors is that we are playing well," van Gaal continued.

"That is maybe a little bit strange but you saw today that we played well in phases but when you lose the ball easily you have to win the duels.

"We lost three duels in the build-up to their first goal after four minutes. In the first half we created a lot of chances but when you see the shots on the goal they were without conviction. I hope it shall not happen again."