Four people have been arrested after an altercation outside Watford's stadium left two men needing hospital treatment.
The injured men sustained cuts and bruises to their faces, according to Hertfordshire Constabulary.
Police were called to Vicarage Road shortly after 5pm on Saturday following Watford's Premier League match against Everton.
Watford supporter Lewis, 31, who did not want to give his full name, said he "heard a lot of shouting" as he was leaving the stadium after the match and "went to take a look".
He said he saw "a Watford fan lying on the floor, apparently unconscious, with blood on his face" and "three Everton fans running from the scene towards the town centre".
He added: "Friends around him were crying and shouting for people to help and call an ambulance."
Images posted to social media show people gathered around someone lying on the floor while an onlooker calls someone a "coward".
A spokeswoman for the force said: "At around 5.10pm, an altercation occurred between a group of men.
"Two sustained cuts and bruising to their faces and have been taken to hospital for further assessment."
Last month Everton supporters were involved in ugly scenes before and after an FA Cup game against Millwall in London.
Videos posted on social media showed fans trading punches and specially trained police were deployed to the Den, in Bermondsey, to help the 200 officers on duty for the match as violence escalated.
