Van Gaal questioned his players' motivation ahead of the 3-0 defeat at Goodison Park, revealing the warm-up ahead of the game had left him worried.
Blind told United Review: "It is always hard to say as you are not going into the game with the feeling that we are only going to give 50 per cent.
"You go into every game thinking you are giving 100 per cent. But I understand what the manager means.
"I can talk for the team and say that everybody knows what has to be done against West Brom, and everybody wants to give 100 per cent in every game."