Ref Watch With Dermot Gallagher : Man. United 2 Chelsea 1

Incident: Chelsea defender Andreas Christensen goes down with a head injury in the lead-up to Romelu Lukaku's equaliser at Old Trafford.

Dermot's verdict: Correct decision, the referee was duty bound to play on.

Dermot says: This proves that football is not an exact science and refereeing certainly is not in so much that if a player is down and the referee thinks he has a head injury, he will stop play. In that incident, the two players' heads clashed, the ball is knocked away, Christensen went down quickly and then chose to get up quickly. But by the time Martin Atkinson has looked round, he is already getting up and that sells in his [Atkinson's] mind that he does not have a head injury - he may well have, but in Martin's eyes, the fact the player has got up would tell him he has not and that is what you have to remember. He then carries on and I would admit, is out of position slightly, which is unfortunate and the game goes on. But I think the referee is duty bound to allow the game go on.

Incident: Chelsea striker Alvaro Morata has a late equaliser ruled out for offside.

Dermot's verdict: Too close to call.

Dermot says: It was so, so tight, but what I would say is that it is not guaranteed to be a goal because irrespective of whether it was right or wrong, the referee blew before he shot the ball in the net. So it would not have been a goal, that is what you have to remember. Whether it was an incorrect offside decision is up for debate as I can't tell what part of his body is ahead, whether it is his arm, whether it is his chest… and I think VAR would have had a long time studying this one.

Credit: Skysports.com