Haase hasn't made it difficult for Djokovic in any of their meetings . I thought that now on clay against a not completely concentrated Djokovic he perhaps could take a set. But no. It seems he simply hasn't the type of game to hurt Novak. His serve is not strong enough and from the back of the court he can't compete with him.
Just needs to learn "controlled aggression". With more motivation for the game instead of pissing around, it would come naturally for him.