21-year-old Filippo Lombardi admitted to being part of a group who threatened unlawful violence before the Liverpool-Roma fixture on 24th April.
However, the Italian denies inflicting grievous bodily harm on Sean Cox, 53, who came away with serious head injuries after he was assaulted outside Anfield.
Mr Lombardi originally denied the violent disorder but changed his plea at a hearing at Preston Crown Court, and is set to face trial next month.
The Roma supporter has been remanded in custody.