Newcastle boss Eddie Howe said it was "very unjust" Liverpool while Isaac Hayden lay on the ground with a head injury in the Reds' 3-1 win.
Howe's side went ahead through Jonjo Shelvey but Diogo Jota's equaliser was awarded by referee Mike Dean despite Hayden lying in the penalty box.
"Two of our players were on the floor and one was holding his head," he said.
"The game should have been stopped immediately because the focus should have been on Isaac's welfare."
Howe, whose side remain 19th in the Premier League table, added: "We had two players out of the game that would be defending that cross and I think that's very unjust.