So, tonight's Dutch Cup match between Ajax Amsterdam and AZ Alkmaar was abandoned after this incident when an idiot fan ran onto the pitch to attack the AZ goalkeeper Esteban. The fan comes running on with a flying kick at the Costa Rican stopper who manages to avoid the idiot before landing a couple of hefty boots himself. Esteban was subsequently sent off by Jeremain Len's best friend Bas Nijhuis after the incident, so the whole AZ team did the decent thing and trooped off behind. The match was suspended and subsequently abandoned.
As we thought, the YouTube video got pulled so here it is on the BBC Sport Website