Juan Mata's second goal for Manchester United in the FA Cup match with Shrewsbury last night has divided referees and football fans - but most of all it's a severe test of the offside laws that were tweaked at the start of this season.
The offside law, Law 11of the Laws of the Game, were tweaked this season to read that players in an offside position must be "mak[ing] an obvious action which clearly impacts on the ability of an opponent to play the ball" in order to be penalised.
Last night, with Mata lining up a free kick from about 25 yards, three Man Utd players stood in an offside position between the defensive wall and the Shewsbury goalkeeper.
As Mata began his run-up, the three United players sprinted out, away from the goalkeeper. It's not clear whether one of the three was still in an offside position when the ball was kicked, but at least one appeared to be offside, although it was tight.
So, should referee Bobby Madley have disallowed the goal when Mata shot the ball over the wall and to the goalkeeper's left and into the net?
It turns out United had approached Madley before the game and asked his advice on a similar trick used by their Europa League opponents MidtJylland of Denmark a couple of weeks ago. And Madley took an unusual position for such a free kick, standing directly behind Mata to follow the flight of the ball.
Because as it turned out, the ball did not pass very close to the three United players, instead flying over the defensive wall and into the net.
That meant that the three players may have been in an offside position, but could not be penalised because their actions did not "clearly impact" the goalkeeper's attempt to save the ball.
He wouldn't have saved it even if the United players hadn't been there.
I wonder if Madley would have allowed the goal if he hadn't known it was coming?