Crewe and Port Vale fans spilled on to the pitch and clashed by the corner flag during Monday's derby match.
More than 100 officers were deployed at Alexandra Stadium but they were unable to prevent trouble both in and outside the ground.
Two fans were arrested for public disorder and assault.
Unrest began prior to kick off when two smoke bombs were let off in Bar 7 on Nantwich Road. Paramedics were called when a young woman suffered an asthma attack as a result of the prank.
But the unrest reached boiling point during Easter Monday's League Two clash as supporters from both sides ran on to the pitch and began throwing punches and kicking each other.