The two fans, a 41-year-old and a 23-year-old, were in the southern Italian port city as part of a group that was visiting from Sweden for the UEFA Europa League face-off between Napoli and AIK Solna later on Thursday.
The injuries sustained by the three men were to the legs and were not life threatening, local daily Il Mattino and ANSA news agency reported.
The reports said the pizzeria owner was injured while trying to defend the Swedish fans against “a group armed with baseball bats and knives”.
However, a spokesperson for AIK told Swedish tabloid Expressen that no Swedish fans had been injured in the incident.
“Several AIK supporters were sitting in a pizzeria and had an Italian friend with then. Then some others came by riding a vespa and cut the Italian friend and the restaurant owner in the leg,” said AIK spokesperson Gabriella Blombäck.
“It wasn’t an incident of supporter violence, but rather an example of what can happen in Naples.”
Blombäck was unable to confirm wither the “Italian friend” was also an AIK supporter.
According to Expressen, there are currently around 900 AIK fans in Naples to cheer the Stockholm club in its bid to advance in the Europa League.