Webb, speaking on Match Officials Mic’d Up, said that while he accepted there would be a difference of opinion, there were valid reasons to rule out the goal.
“Interfering with an opponent when the player in an offside position is not playing the ball and referees have to judge whether that player’s actions impact an opponent are some of the most subjective decisions we have to make,” Webb said.
“So it’s not surprising that some people believe this goal should have been upheld, so I think it’s important that we look at the facts of what actually happened in this situation.
“We know that the corner comes and the ball reaches Van Dijk. When the ball crosses the penalty area, the Manchester City players come out and leave Robertson in that offside position in the heart of the six-yard box.
“When Van Dijk heads the ball forward, that’s the moment we have to judge Robertson’s offside and what he’s doing there.
“We know he doesn’t touch the ball, but what does he do? Well, when the ball moves towards him, three meters from the goal, right in the middle of the six-yard box, he does that clear action of ducking under the ball.
“The ball goes just over his head and finds the goal in the middle of the small area where it is located. Then the referees have to make a judgment: did that clear action affect Donnarumma, the goalkeeper, and his ability to save the ball? And that’s where subjectivity comes into play.
“Obviously that’s the conclusion they came to. They looked at that position, they looked at that action, so close to the goalkeeper, and they formed that opinion.
“I know that it is not an opinion shared by everyone, but I think it is not unreasonable to understand why they would reach that conclusion.
“The player is so close to the goalkeeper, the ball is coming straight at him and he has to crouch down to get out of the way of the ball, and they come to the conclusion that it affects Donnarumma’s ability to dive towards the ball and make that save.
“And then, of course, once they’ve made that decision on the pitch, the VAR’s job is to look at that and decide: was the offside result clearly and obviously incorrect?
“Only Donnarumma really knows if he was affected by this and of course we have to look at the factual evidence, and when we see that factual evidence of that position of the player crouching under the ball, so close to the goalkeeper, the VAR determines that the result of the offside is not clearly and obviously incorrect, and they stand aside.”
