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: Should Manchester United defender Lisandro Martínez have been sent off at Crystal Palace? Did Arsenal's Gabriel Martinelli foul Manchester City goalkeeper Éderson before Gabriel scored? And was there a case for a red card for Tottenham Hotspur 'keeper Guglielmo Vicario?
Crystal Palace 0-0 Man United
Possible red card: Martínez challenge on Kamada
What happened: Manchester United were on the attack in the 63rd minute when the ball ran loose to the edge of the area. Crystal Palace midfielder Daichi Kamada went to challenge Lisandro Martínez, with the United player appearing to go into the challenge two-footed. Referee David Coote awarded a free kick to Palace and booked Martínez.
VAR decision: No red card.
VAR review: The VAR, Chris Kavanagh, decided that as Martínez didn't make any contact with Kamada, the yellow card shown on the field was an acceptable disciplinary outcome, but it's difficult to see how this challenge could ever be considered a footballing action. Neither does the law demand that a player must make contact with an opponent for it to be a red card offence.
Martínez jumped in directly towards Kamada, stamping down onto the ball in a way that must be seen as endangering the safety of an opponent. How can there be a justification for trying to play the ball in this way? Martínez should have been sent off.
Luton Town midfielder Jacob Brown escaped a VAR red card for a similar challenge against Manchester City last season, jumping in with both feet and getting contact on the ball. Brown led into Phil Foden with one foot rather than two, and while there was slight contact opponent's leg there wasn't the stamping motion.
The Premier League's Independent Key Match Incidents (KMI) Panel unanimously voted that referee Tim Robinson and VAR Jarred Gillett had missed a red card for serious foul play. It noted: "The attacker gets away with this challenge because he wins some of the ball, but the technique of the tackle jumping in with two feet is shocking and very dangerous."
You could copy and paste that description into this incident.
Possible penalty: Handball by Lacroix, Lerma
What happened: United delivered a free kick into the area in the 68th minute, it flicked off the head of Palace's Ismaïla Sarr before appearing to touch the arm of Maxence Lacroix and then Jefferson Lerma. The ball ran behind for a corner.
VAR decision: No penalty.
VAR review: Handball is going to have to be blatant for the VAR to get involved this season, with the interpretation moving closer to where it was a few years ago. But even with a more relaxed approach, this wouldn't have resulted in a penalty last season either.
Both Lacroix and Lerma have their arms in positions that are justifiable by their movement, not extended away from the body, and neither places their hand to the ball.
Man City 2-2 Arsenal
Possible foul before goal: Martinelli on Ederson
What happened: Arsenal took the lead in first-half stoppage time when Gabriel Magalhães headed home a corner from Bukayo Saka, but was there a foul on goalkeeper Éderson as the cross came over? (watch here)
VAR decision: Goal stands.
VAR review: This was almost a carbon copy of a corner routine from a few minutes earlier. Saka delivered to the back post to find the run of Gabriel, with Gabriel Martinelli placing himself behind Ederson to create a blocking position.
This may well lead to a VAR intervention in the other top European leagues, with contact on the goalkeeper in the six-yard area, but there are many examples of it not being penalised in the Premier League.
If an attacking player stands his ground or makes no clear move into the path of the goalkeeper, it's seen as normal football contact and that's why there was no intervention by the VAR, John Brooks.
Arsenal were on the receiving end of such a decision two years ago when Aston Villa's Douglas Luiz scored direct from a corner. Boubacar Kamara was accused of blocking off Arsenal goalkeeper Aaron Ramsdale, but the VAR determined the Villa player hadn't moved and there was no foul.
And last season Tottenham Hotspur goalkeeper Guglielmo Vicario conceded goals against Man City and Everton when the opposition placed players in front of him to prevent a clear run at the ball.
It comes down to whether you think a goalkeeper has a right to a clear run at the ball, or whether it's their responsibility -- or that of a teammate -- to make sure they are not blocked in. You can also argue that Ederson got himself into a poor position on both corner routines.
Possible red card: Haaland for throwing ball at Gabriel
What happened: After Man City equalised in the eighth minute of added time, Erling Haaland picked the ball out of the back of the net and threw it at the head of Gabriel as he ran back up the pitch. (watch here)
VAR decision: No red card.
VAR review: It's petulant, but the suggestion we should be seeing VAR red cards for this is wide of the mark. It was looked at by Brooks but not deemed to be an act of violent conduct.
We see players kick and throw the ball at opponents regularly, but they are never sent off for it. That's not to say you couldn't argue the case within the law, but Haaland would really have had to throw the ball with far more force or brutality for the VAR to consider this to be a red card -- but the City striker would have been booked had the on-field officials seen it.
As the VAR looked at it there can be no retrospective action, not that it would have reached the threshold for a charge. Although the possibility of retrospective action still exists, VAR means the chances of an incident not being looked at by any of the officials are extremely slim. So, as a consequence, it doesn't happen anymore.
West Ham 0-3 Chelsea
Possible penalty: Fofana challenge on Summerville
What happened: West Ham United were 2-0 down and on the attack in the 28th minute when Crysencio Summerville tried to latch onto a pass from Lucas Paquetá. Summerville had his arm held by Chelsea defender Wesley Fofana and went to ground. Referee Sam Barrott waved away the penalty appeals, and it went to the VAR, Stuart Attwell.
VAR decision: No penalty.
VAR review: This is all about judging the impact of a player's actions, and plenty will feel that Fofana has prevented Summerville from getting onto the pass, and it should be a spot kick.
We've seen a number of similar situations not result in penalties, where the holding was not prolonged, and that didn't cause the attacker to go down in the way he did.
So, the VAR is considering whether the holding really did impede Summerville in the way he is suggesting. Attwell will take into consideration how long Summerville has been held, and if the player has gone over in a theatrical way; does that fit the nature of the holding?
Attwell decided that the holding was only "fleeting" and Summerville went down too easily. It's right on the edge of an intervention, but it perhaps doesn't quite reach the Premier League's the high bar.
We may see the KMI Panel say this should have been given as a penalty on the field, but it didn't reach the threshold for VAR. West Ham benefitted from this earlier in the season for the spot kick they won against Aston Villa. The KMI panel deemed referee Tony Harrington shouldn't have given it, but also said it was subjective and not enough of an error to warrant the VAR to cancel the penalty.
The high bar has meant that VAR in the Premier League hasn't reached outcomes which, to many, would be fairer. But PGMOL and the Premier League would say that it's the perfect example of "referee's call" -- so whichever way it's given it remains an on-field decision, as it sits within the corridor of subjectivity where either outcome is acceptable.
At this point last season there had been seven subjective VAR interventions, while this season there's been only three -- one of which was for offside. It's a small sample size and too early to draw conclusions over the number of interventions, and in truth there has been far less controversy with refereeing decisions this season.
Tottenham 3-1 Brentford
Possible red card: Handball by Vicario
What happened: Yehor Yarmoliuk crossed into the area in the 58th minute, with Tottenham goalkeeper Vicario coming out to claim the ball ahead of Mikkel Damsgaard. Vicario took three touches to keep the ball away from Damsgaard, but the third was outside the area. The refereeing team allowed play to continue, with Kristoffer Ajer booked for his protests.
VAR decision: No red card.
VAR review: There's a common misconception that handball outside the area is an automatic red card, but the goalkeeper must be denying an obvious goal-scoring opportunity (DOGSO).
Vicario's first two touches are important, as they come when the ball is inside the area and take the ball behind Damsgaard and away from goal. That means the direction of travel is away from goal, Damsgaard doesn't have a realistic chance to get immediate control of the ball and two Tottenham players would have the ability to close him down.
If Vicario had handled the ball outside the area and it was going towards goal for Damsgaard to run on to, that would be a clear case of DOGSO.
As it's not DOGSO, the VAR cannot get involved to tell the referee, John Brooks, that a handball has been missed so a free kick and a yellow card should be awarded. The real question is for the assistant, as he had the key view to spot that Vicario had handled outside the area.
It should have been a booking and a free kick to Brentford, but nothing more than that.
Some factual parts of this article include information provided by the Premier League and PGMOL.