Video Assistant Referee causes controversy every week in the Premier League, but how are decisions made, and are they correct?
After each weekend we take a look at the major incidents, to examine and explain the process both in terms of VAR protocol and the Laws of the Game.
In this week's VAR Review: Was Brentford's Christian Nørgaard lucky to escape a red card at Arsenal? Should Liverpool have been given a penalty for handball by James Ward-Prowse? And how did semiautomated offside go in its first weekend?
Arsenal 1-1 Brentford
Possible red card: Challenge by Nørgaard on Martinelli
What happened: In the 28th minute, Gabriel Martinelli made a run down the left flank as Christian Nørgaard gave chase. The Brentford midfielder attempted to win the ball but went through Martinelli in trying to do so. Referee Simon Hooper produced a yellow card. It was checked for a serious foul play red card by the VAR, James Bell.
VAR decision: No red card.
VAR review: Should Nørgaard have received a red card which would have reduced Brentford to 10 men for over an hour? Or was a yellow card a justifiable disciplinary outcome?