Van Gaal was disappointed that his side failed to convert their chances against Schalke.
“It is unbelievable. If we waste so many chances then it is to be expected that they score from their first attempt,” van Gaal told Sky after the game.
“I can’t put the ball in the net myself. It is unbelievable if we analyse the entire game. The goals are the most important and we have seen that once again today.”