Three people died after being run over by four-wheel drive vehicles and two of the others killed were policemen, the report stated, quoting local officials.
The riot in the town of Dakhla began after Mohammedia club Chebab, from just north of Casablanca, beat the local Mouloudia club 3-0.
Rival fans began throwing stones at each other and then “criminals” took advantage of the situation to attack people with knives and clubs, a statement from the Oued-Eddahab-Lagouira province said.
Initial reports put the toll from the incident at two dead and 27 wounded.
Eight vehicles and local businesses were also burned in the rioting. The incident is under investigation.
Morocco annexed the former Spanish territory of Western Sahara in 1975 and an armed movement known as the Polisario is fighting for independence.
The two sides are in talks over the future of the territory but an eighth round of informal negotiations held over the summer in the United States failed to yield any progress.
Morocco has offered wide-ranging autonomy to the mineral-rich Western Sahara while the Polisario Front wants a referendum with independence as an option.