Up to 100 football hooligans took part in an organised street fight as Brighton and Hove Albion played a pre-season match.
Groups descended on the city to take part in the pre-arranged stand-off.
Residents and publicans locked their doors as two gangs clashed in Grove Hill, Brighton.
A team of 20 police officers stormed the scene and the group scattered in different directions.
Eleven people were arrested on suspicion of violent disorder.
The clash took place at about 4.30pm on Saturday.
The people in custody were expected to be released on bail late last night.
Anyone with information is asked call Sussex Police on 0845 6070999 quoting Operation Muswell.
Read the full story in today's Argus.