At this stage in the process, the (yellow) offside line has been completed on Mings.
The VAR is now setting the offside point to Firmino.
He has already set the point on the armpit. Now he needs to set the centre of gravity (marked by the feet).
The VAR is now setting the offside point to Firmino.
He has already set the point on the armpit. Now he needs to set the centre of gravity (marked by the feet).
The VAR at first selected this point as being the centre of gravity - close to Mings' hand and what the VAR thought was the foot of Firmino.
That created this initial black offside line to Firmino, so when it was deleted, many have cried foul.
Remember, offside lines are not final until they are red and blue, this is the calculation stage.
Remember, offside lines are not final until they are red and blue, this is the calculation stage.
However, at this point the VAR and the RO noticed that Firmino's foot could just be seen through the legs of Mings. And this creates the true centre of gravity for the imaging software, not the first calculation.
This means the Firmino offside decision was re-calibrated based on the correct measurements to the attacking player's foot between Mings' legs.
And that is the full process whereby the VAR had to recalculate to reach the decision that Roberto Firmino was offside based on the technology and evidence available.
Here's a little explanation of the centre of gravity and why it's important.
