The Red Devils are under pressure to beat the Hammers after managing just one victory in their opening five Premier League games under the Dutchman.
However, Van Gaal insists that he needs time to implement his philosophy at Old Trafford and won’t expect too much from his players during the period of transition.
“I don’t think my players are robots – they are human beings and human beings make errors,” said Van Gaal, whose side lost 5-3 at Leicester on Sunday.
“I am also a manager who always wants to evaluate and discuss things. That’s the way I do things. I have done it, this week is no different.
“It’s happened, it’s about overcoming things. It’s not a regular occurrence – when you see our figures in the Premier League, apart from this [Leicester] match, then we are defending well.
“The average is conceding less than one goal I think and we have scored a lot of goals. I think we are fifth or sixth [in this situation]. I see it differently to a lot of journalists.”
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