Manchester United manager Louis van Gaal has insisted that his methods are working despite his side's one-sided Europa League loss to arch rivals Liverpool and struggles in the Premier League.

United's 2-0 defeat at Liverpool on Thursday left them facing elimination from the Europa League and with Van Gaal's side three points below the top four in the Premier League, having played a game more than fourth-place Manchester City, their hopes of Champions League qualification are fading.

United continue to search for an identity under Van Gaal and were well beaten by Jurgen Klopp's effervescent Liverpool, but the Dutchman cited injuries, suspensions and the strain of competing on three fronts as mitigating factors.

"I think it is working, because you have to see how we have to work and under which circumstances," said Van Gaal, whose side host West Ham United in the FA Cup quarter-finals on Sunday.

"When you don't have too many players and you have to play in three competitions, it is very difficult to play.

"The (playing) style is also working. It is not giving the best results. It is not good enough when you think that you have to be champion or win the Europa League or the FA Cup.

"It is still possible, but when you see this game, you can say that (it is not working). But when you analyse what we have done this season and last season, you cannot say that."

Asked by a reporter during his Anfield post-match media conference why United have not managed to win more than four games in a row this season, Van Gaal said it was due to the need to manage the resources in his squad.

"Because I have to change always my team," he said. "I cannot play the same line-up in many matches.

"It is also because of the full schedule. Every manager in the Premier League is rotating and it is necessary, but I have to rotate because of injuries or tired players. That's difficult, that is not so easy.

"That is also cheap for me to say that. And I don't want to hide (behind) the injuries or something like that. We are still in three competitions. So we can fight for a lot.

"And it is possible that we are going out. And then it is again a very difficult situation for everybody. But still we have the chance to win something and you have to believe in that.

"I see a lot of your colleagues are not believing in that. But that was already for a long time. There are many colleagues of mine not in three competitions anymore."

With West Ham's visit on Sunday followed by the last 16 return leg against Liverpool on Thursday, United's chances of salvaging any silverware from their season could be over by the end of next week.

But Van Gaal was unwilling to countenance the suggestion that the outcome of those two matches could have a decisive impact on his Old Trafford future.

"I don't want to discuss that with you because you are not part of the people who determine (what happens)," he said.

"It of course gives much more pressure. We are in three competitions and after the defeat in Midtjylland (in the Europa League), you have sacked me already and then we're standing up and we are in the next round.

"And that is possible also against Liverpool. We have to play that match for the second time, at home, and maybe we can score three goals.

"It shall be very difficult, I know that, but it is not impossible. Against West Ham United it is also possible. In Old Trafford we have normally won our games."