Utrecht secured a 1-0 triumph over Kozakken Boys at the 5,000-seat Sportpark De Zwaaier, but the celebration turned disorderly when traveling supporters entered the pitch at full-time.
Fans from the FC Utrecht side marched onto the field and confronted the home supporters, prompting a large scuffle that required security staff to step in.
Separated only by the advertising board along the sideline, the two groups began hurling objects, including a wheelie bin thrown from the stands.
Dutch football reporter Jeroen Kapteijns posted video of the incident on social media, noting, "Things get pretty out of hand after the final whistle in Werkendam, with black-jacketed folks going at each other." He added, "Such a shame for cup football to have this kind of brainless idiots." and identified the black-jacketed fans as members of the FC Utrecht section attacking the home supporters.
Utrecht's victory came thanks to a first-half goal by Nikolas Panagiotou, securing their place in the second round of the KNVB Cup.
