It is a game of fine margins and that was particularly evident when VAR showed just how close Lionel Messi's second goal in the World Cup final was to being offside.
Argentina won the World Cup on Sunday after beating France in a penalty shootout. It came after 120 minutes of incredible action that saw the game end 2-2 after 90 minutes before both sides scored in extra time. Messi put the South Americans 3-2 up in the 108th minute - but by the barest of margins.
For starters, his goal needed the referee to check his watch to ensure the ball went over the line. Prior to that, the 35-year-old sent Lautaro Martinez clear and his shot was parried into the path of Messi, who converted from close range. Martinez was only onside by a matter of centimetres - as the images show.
It was Manchester United defender Raphael Varane who played the Inter Milan star onside. The Argentina players didn't wait for the goal to be confirmed as they reeled away to celebrate with Messi, whose strike came in the 108th minute - 10 minutes before Kylian Mbappe equalised from the spot to complete his hat-trick.
VAR was used for the first time at a World Cup four-and-a-half years ago in Russia and was one of the main talking points of the tournament, even if it was largely in its infancy. The technology was used in the final, as it was on Sunday, although it has moved on as new systems are implemented.
In Qatar, FIFA used an innovative limb-tracking technology which has been undergoing trials for years. The AI technology uses 12 tracking cameras to create three-dimensional models of a player’s skeleton to determine whether any part of their body is offside.
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The system aims to reduce the time it takes to make a decision while offering greater clarity to supporters. The 3D images are shown on big screens in the stadium and FIFA made it available to its broadcast partners, which included British channels BBC and ITV, thus allowing them to see the same image as those in the stadium.
Despite the forward strides made, errors have still occurred and Argentina were on the receiving end of one earlier in the tournament. They began their World Cup in the worst possible way - losing 2-1 to Saudi Arabia in what is one of the great shocks of international football.
However, whilst leading 1-0, they were denied a second when Martinez was deemed to be offside. However, the individual operating the system didn't measure Martinez against Saudi Arabia's deepest player, Yasser Al-Shahrani. Had he done so, the goal would've stood and Argentina may not have been toppled by the Middle Eastern minnows.
