A Madrid court has ruled that a minor must be detained at a juvenile centre for six years after being found guilty of homicide in the 2014 death of a Deportivo La Coruna fan.
In November that year, a brutal street fight erupted between rival "ultra" groups before a match between Atletico Madrid and Deportivo.
In the violence, 43-year-old Deportivo fan Francisco Javier Romero Taboada, known as "Jimmy," was beaten and thrown into a river.
Emergency services rescued him from the water, but he later died in hospital.
The minor, identified only by his initials A.C.G. in Monday's court statement, will also serve two years of supervised probation after completing his term of detention.
Further sentences are expected in a case that saw police make 82 arrests following the violence.