Police were called before the Watford v Luton game on October 23, after they were informed that bottles were being thrown by fans.
One man reportedly suffered a minor injury to his head during the incident.
Officers arrived at Vicarage Road at around 11.40 am, following reports of minor disorder. They arrived shortly and had the situation “under control”. Enquiries are continuing.
No arrests were made, as confirmed by Herts Police.
Their statement said: “There was a significant policing presence in the area throughout the day and, although there was some minor disorder among a handful of fans before and after the game, the event passed without major incident.”
The Hornets beat Luton Town 4-0, with goals by Ismaïla Sarr, João Pedro, Keinan Davis and William Troost-Ekong.
The win boosted Watford to 10th in the second-tier standings. Their next match against Luton will be on April 23.
The clubs have been rivals since their first match in 1885.
Picture credit Shutterstock/Michael715