Sheffield United boss Chris Wilder, speaking to BBC Sport: "A missed opportunity. I am OK with that performance, it was always going to be difficult against a team that never shifted. The first goal is really important and it is super difficult when you go behind against a team like Newcastle.
"I was told at the start of the season that the linesman would not put his flag up and let it go. He put his flag up and the referee was about to blow his whistle.
"Everyone in the ground stopped. Jonjo Shelvey even nonchalantly went up and took an opportunity. His body language said to me he had seen the linesman had put the flag up and he was going to be offside.
"The game has changed. This game now is completely different to what I experienced as a 16-year-old lad as an apprentice. This game in a heartbeat has changed. I don't know where it is going and it is sucking the life out of me and the supporters."
Newcastle boss Steve Bruce: "I was delighted with the spirit of the players. To come here has never been easy over a number of years. Chris Wilder has done a remarkable job."
On the second goal: "Down the line we are going to have a few that will go against us. I have to say well done to Jonjo for keeping on going. If that is an opportunity the linesman keeps his flag down because it looked borderline. Maybe he could have kept the flag down and checked later. Ultimately it was the correct decision.
"The referee will not blow the whistle and he has done that. Usually it is clear and obvious for the linesman to put his flag up but let's remind everyone it was the second goal, which wasn't important anyway."