Chelsea and Manchester City fans clashed with police on Thursday night in Porto before the Champions League final on Saturday.
Portuguese authorities have enforced a strict 10.30pm bar curfew to combat the spread of COVID-19 in the country, which was seemingly the cause of the aggravation.
According to The Mirror, the shutting of pubs and bars throughout the city appeared to irk some of the football fans and the curfew came as a shock to many.
One Chelsea fan as left drenched in blood, while some City fans were involved in skirmishes with the police.
Both sets of supporters had mingled happily together throughout the evening chanting, ‘Who the f*** are Man United?’
In a separate incident, City and Chelsea fans clashed in a city centre street as they returned to their hotels following the 10.30pm curfew.
Mobile phone footage posted online showed the supporters fighting, before police stepped in to break it up.
Mayor of Porto Rui Moreira said one person was taken to hospital but their injuries are “nothing serious”.
He told Sky Sports News: “As far as I know, and I spoke with the police this morning, it was nothing serious.
“We had to shut down the bars and the pubs because that’s the law, the curfew law, by 10.30pm people had to leave.
“Between the fans, there was some aggression. One guy went to hospital, it was nothing serious, no arrests.
“People went to their hotels and it always happens. We have this experience also with our national games.
“You can’t change it, that’s life, but nothing that concerns us so far.”