Five football fans were taken to hospital with breathing difficulties after an Eredivisie game between PSV Eindhoven and Ajax saw thick smoke bombs let off just minutes in.
The unsavoury scenes (below courtesy of @ElzenHD) that unfolded on Sunday went viral on social media, and very much overshadowed the game, which finished 1-0 to hosts PSV thanks to a 25th minute strike from Jurgen Locadia.
The smoke bombs were set off as early as the fifth minute of the crunch clash by the home fans, and quickly engulfed a substantial section of the crowd, causing the referee to temporarily half the game whilst it cleared.
It is understood that the actions of the PSV faithful were in protest at recent banning orders enforced upon them by the club.
— From The Stands (@FromTStands) 23 April 2017
Unfortunately, the show of defiance resulted in five supporters being admitted to hospital after suffering respiratory problems because of the thick smoke.
It was a crushing defeat for Ajax, who could have closed the gap on leaders Feyenoord to just a single point - significantly, they are now four points behind with only two games remaining.
Ajax haven't won the league title since 2014, and usually fight it out with PSV over in the Netherlands for the crown - the two sides have amassed a staggering 56 victories between throughout the course of history.
For Feyenoord, who are managed by Giovanni van Bronckhorst, one more victory will see them secure a first league triumph since 1999.