Barry was waiting on the shoulder of Guehi, weighing up when to make his move as Rohl played a through ball.

It was not a good pass by the German midfielder, straight to the feet of the Manchester City defender.

While Barry had started to move towards Guehi, he was not placing the opponent under pressure. Inexplicably, Guehi under hit a back pass which Barry latched on to to score.

Barry was offside and the assistant raised his flag to disallow the goal initially, but he was quickly overruled by Oliver.

The law asks a few key questions: Did Barry do anything which could have caused Guehi to rush, or to influence his poor pass?

Barry did move towards the ball, but did that really impact Guehi?

And did Guehi have full expectation of a controlled outcome from playing the ball?

“Barry is in an offside position when the ball is played but it’s down to Guehi,” former Manchester City and Everton defender Andy Hinchcliffe said on Sky Sports.

“He is in control of his actions, so suddenly the attacker goes from offside to onside. That is why the goal rightly stands. That is disastrous from Guehi.”

Without these subjective judgements, you would have to penalise every player just for being in an offside position – even if they were not close to the opponent.

Guehi’s mishap is among the most obvious examples of a pure defensive howler, and clearly should cancel any offside.

But we’ve seen far more controversial ones, such as Bruno Fernandes’ goal in the Manchester derby three years ago.

Marcus Rashford, from an offside position, ran after the ball but he did not touch it and Fernandes came in from behind to score.

Everton have prior experience, too.

In April last year, Liverpool‘s Luis Diaz was standing offside behind James Tarkowski as the centre-back attempted to intercept a loose ball. It resulted in Diogo Jota scoring the winning goal for Arne Slot’s team.

Some take issue with this rule because, as in those two cases, it can inadvertently disadvantage defenders who know there is an opponent close by, but do not know they are offside.

In Tarkowski’s case, would he have acted differently if Diaz was not there?

It is not something you can fix easily. You would have to make offside completely binary, and loads more goals would be ruled out.