According to reports in the UK, the victim is 41-year-old restaurateur Marco Ficini, who was in Lisbon to watch the derby on Saturday night.
He was killed after being run over and dragged along for over 30 metres.
PJ police are investigating but local media reports in Portugal indicate he may have been intentionally mowed down by a Benfica supporter.
The victim’s brother has arrived in Portugal to have the body flown to Italy.
PJ police have meanwhile revealed that they have recovered a car believed to have been used in the incident, saying they had found a white Peugeot parked at a villa in Amadora which has since been taken by PJ police for examination.