Switzerland's Breel Embolo became the first player to be sent off for mistaken identity in the World Cup when he was dismissed against Argentina in the quarter-finals.
With the score locked at 1-1 in the huge last-four clash in Kansas City, Embolo received his marching orders after initially winning a free-kick when the referee thought he had been fouled.
At first, the Swiss forward Embolo appeared to be fouled near the half-way line by Argentina's Leandro Paredes, who was booked.
However, the referee was alerted by the VAR to check the incident under the new mistaken identity rule, with the replay then clearly indicating Embolo had simulated contact.
Amid the drama and some confusion, the Paredes booking was quashed and Embolo, who had already been booked, was shown a second yellow and therefore a follow-on red card.
It changed the complexion of the game as, suddenly, Argentina had a man advantage and went on to win the tie in extra-time 3-1, setting up a mouth-watering semi-final showdown with England on Wednesday.
What is the World Cup rule on mistaken identity?
The new mistaken identity rule was brought in just before the World Cup, reportedly at the direct behest of FIFA referees' chief and former top official Pierluigi Collina.
The new law states: "Mistaken identity is reviewable when a player is shown a yellow/red card but the offence for which the card was shown was committed by another player of either team."
Why has this rule been introduced?
The rule was brought in because of fears an incorrect decision could lead to punishing an innocent player, as in the case of Embolo where he initially was deemed to be fouled and his opponent was reprimanded, before it quickly became clear the Swiss ace was actually in the wrong.
As with the other decisions the VAR can review, it is hoped the new rule will eliminate as many human errors as possible, while quickly being able to correct any clear and obvious officiating errors.
How can the rule be enforced?
The rule is enforced when the VAR informs the on-field referee that a mistake has been made after reviewing it in the control room.
The referee will then receive instructions from the VAR and is likely to be sent to the pitchside monitor to check the specific incident before making a ruling and announcing it to the stadium.
There is an important aspect to remember, though, that the VAR can only intervene in cases of mistaken identity if a yellow card has been, in their view, incorrectly shown.
Therefore, in the Paredes-Embolo tangle, if the Argentina man had not been booked there would have been no opportunity for the remote officials to intervene on the dive, so the Rennes man would have survived.
Even though the rule saw Embolo eventually punished for diving and the lawmakers may have had incidents of diving that the referees miss firmly in their minds when drawing up the legislation, it can also be used on other occasions during games.
How has the rule been used in the World Cup?
In the group stage, USA's Tim Ream became the first player to benefit from the new rule against Paraguay.
The centre-back had a yellow card rescinded for what was originally ruled to be a foul on Paraguay's Miguel Almiron.
It was overturned after the VAR judged it as simulation from the former Newcastle man after a review.
That incident did not lead to a sending-off, though, and the rule had not been activated again in the tournament until Sunday morning's quarter-final between the Swiss and Argentina when Embolo was deemed to have dived.
