Spectators at the Stade de France glimpsed football's possible future when a video referee intervened to correct two offside decisions in the second half of Spain's 2-0 win over France.
The friendly was used to further trial the use of video technology, with officials instructed to keep an eye on goals wrongly allowed or disallowed, straight red card offences, penalty calls and cases of mistaken identity.
Antoine Griezmann saw his 48th minute 'goal' chalked off when he headed home Layvin Kurzawa's back post knock-down before technology took its course.
Referee Felix Zwayer received a message in his ear-piece from the video official, sat in a television truck outside of the stadium, that both Griezmann and more blatantly Kurzawa were offside from Christophe Jallet's cross.
The scenario was reversed later in the half, when Gerard Deulofeu converted Jordi Alba's teasing delivery only to have his celebrations curtailed by the linesman's flag, before recommencing them once the video referee intervened to say the goal was legitimate.
The system was trialed at the Fifa World Club Cup to much derision, but advocates will be encouraged by the way in which correct decisions were arrived at promptly in Paris on Tuesday.
The Football Association want to stage their own trials in the third round of next season's FA Cup, which could also be a policy to stir up interest in a competition increasingly consigned to the margins.
Fifa president Gianni Infantino would also like the system to be used at the World Cup in Russia next year.
Doubts remain over how the game should restart should the video referee be forced to intervene while the ball is still 'live', and the system also promises to change the nature of goal celebrations in the stands.