 "Griezmann scores penalty after video review: All you need to know about VAR")
There has been a lot of defining moments in Fifa World Cup 2018 where VAR has been used to award a penalty.
Here's all you need to know:
The referee makes the sign of a screen with his fingers and goes to consult a screen on the edge of the pitch — the controversial VAR, video assistant refereeing system, has made its debut in FIFA World Cup 2018 at Russia.
After experiments in different FIFA tournaments, Serie A in Italy and the German Bundesliga this season, the principle is now well known in most countries. VAR can be used in four scenarios -- after a goal has been scored, for penalty decisions, red card decisions or for a case of mistaken identity of a player who has been booked or sent off.
"It's about avoiding major and obvious mistakes, not refereeing with technology, the goal has never been to check every minor incident," explained Pierluigi Collina, chairman of the FIFA Referees Committee, during a VAR training programme organised at the Italian national training centre at Coverciano near Florence.
In Russia, 13 referees will officiate exclusively by watching the control screens. And some of the 35 referees selected to officiate on the pitch will also move into the role of video referees for one or more matches.
"VAR can be our best friend, it's no longer possible to make a crucial error," said Dutch referee Bjorn Kuipers.
The main sticking point remains the inexperience of some of the referees who have rarely got to use the new technology before the World Cup.
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"All the referees involved have participated in numerous tournaments where video assistance has been used," insisted French referee Clement Turpin to AFP.
How does video assistant system (VAR) work?
Behind VAR, there will be the VOR -- Video Operation Room -- where the numerous assistants will be seated, along with four technical operators.
"There will be four video officials. The main VAR communicates with the central referee and can suggest whether he should come and check footage," explained Roberto Rosetti, in charge of VAR for FIFA.
"The VAR assistant No.1 follows the match live, the No.2 deals specifically with offsides and a third assistant is responsible for supporting the main VAR, to verify the respect of protocol and ensure good communication between the team," added the Italian.
FIFA will have a single operational centre -- as is the case in the Bundesliga -- which will be installed in Moscow and connected to all stadiums via a fibre optic network.
Collina -- formerly considered one of the world's finest referees -- also stressed that VAR officials would never have to cover more than one match a day.
"I was asked why the VARs would have to wear a referees' kit. It's because they sweat like they do on the pitch, it's not like watching a game on the couch while drinking coffee," said the 58-year-old.
The question of offside decisions remains extremely complex.
"It all happens so fast, that now we can say: 'If I really have a doubt, I let the player go and if he scores, we'll check the video'. It removes pressure," said French assistant referee Cyril Gringore.
Two additional cameras will be used at the World Cup, exclusively dedicated to offside decisions. They will be "installed at a height to reinforce an area that, despite the 33 cameras used by broadcasters, was not covered optimally", explained Sebastian Runge, head of FIFA's Technology Innovation Group.
In all cases, messages will be broadcast on giant screens in stadiums so spectators can see what decision is reached by VAR: goal, no goal, offside. But no replays will be shown until the on-pitch referee has made his decision.
"No slow motion will be broadcast before the decision is made, we don't want the referee to be influenced by the crowd," added Runge.