England keeper Pickford escaped punishment for his reckless challenge on van Dijk.
And Hasenhuttl said: “It was a horrible tackle to be honest.
"We have more often the situation now that the game goes on although it is offside and then some duels happen that don't have to happen normally. This is an issue. But you cannot go like this into a duel.
"This is an absolutely disastrous tackle. And I think sure it can be a red card but in the end it is a quick decision from the referee and then it wasn't. But the tackle by itself, when you only see the tackle, was horrible yes."