India, June 28 -- Colombia thought they had found the moment that would give their Group K dominance a perfect finish. Deep into the closing stages against Portugal in Miami, Davinson Sanchez rose inside the box, met a cross from the right phase of a set-piece move and headed the ball down into the net. For a second, the Colombian end exploded. Then came the flag. Then came VAR. Then came the image that explained everything: Sanchez was offside by the smallest possible footballing margin - a toe.

The decision was brutal, but it was not mysterious. Colombia had taken the corner out towards the edge of the penalty area, meaning the protection normally attached to a direct corner no longer applied. From the next cross, the usual offside law...