Louis van Gaal says Manchester United's injuries have hampered his work this season

Louis van Gaal insists he is doing a good job at Manchester United and could yet deliver a trophy this season.

A one-sided 2-0 defeat at Liverpool in the first leg of their Europa League derby brought heavy criticism from some of United's most successful ex-players, and left Van Gaal facing a fresh round of questions about his Old Trafford future.

But the Dutchman has faced down his critics all season, and with West Ham due in Manchester for Sunday's FA Cup quarter-final, the United boss has again defended his record.

"I think it is working, because you have to see how we have to work and under which circumstances," said Van Gaal, in reference to the injury problems which have contributed to his use of 31 players this season.

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

"The 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 [Liverpool] 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.

Manchester United lost 2-0 at Liverpool in the Europa League on Thursday night

"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.

West Ham boss Slaven Bilic has sympathy for Louis van Gaal and says he expects an improved Manchester United team for Sunday's FA Cup quarter-final West Ham boss Slaven Bilic has sympathy for Louis van Gaal and says he expects an improved Manchester United team for Sunday's FA Cup quarter-final

"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."

Asked whether the games against West Ham and Liverpool could decide whether he stays at United, Van Gaal said: "I don't want to discuss that with you because you are not part of the people who determine [what happens]."