He lost three fingers while another fan standing next to him suffered burns to one of his arms, reported Blick.ch
Thirty other people were injured as they were trying to escape from the cloud of smoke created by the explosion. FCZ said in a statement they were "shocked by the events in Rome's Olympic Stadium" and condemned the incident in the strongest terms.
Sports director Fredy Bickel said the kind of behaviour that led to the injuries was “simply incomprehensible.”
FCZ said they would do everything in their power to bring the person responsible to justice. Moreover, the club announced it would give up its ticket allocation for the next Europa League away game, due to be held on December 1st against Sporting Lisbon.
FCZ said they were also considering additional measures to prevent incidents like the one in Rome, Blick.ch reported.
Hooliganism has been a long-standing problem in Switzerland. The incident in Rome comes just weeks after violence broke out during the derby game between Grasshopper FC and FC Zurich, the first time in the history of Swiss football that a professional match was abandoned due to rioting.
FCZ lost 1-0 to Lazio in the Europa League group match against Lazio and now on the brink of being eliminated from the Europa League championship.