Lazio president Claudio Lotito insists the attack on Tottenham fans in a bar in Rome was not carried out by supporters of the Serie A side.
At least one Spurs fan was left seriously injured and nine others were hurt after being set upon by a group of masked assailants outside a pub in the Italian capital.
The two teams meet in the Europa League clash on Thursday evening, but Lotito is adamant the "cowardly" attack was not carried out by supporters of his club.
According to Ansa Agency, a Roma supporter has been arrested and 15 other people, including both Roma and Lazio fans close to right-wing extremist movements in Rome, are under investigation.
In a statement, the club reiterated their belief that Lazio fans were not involved on the attack, and once again urged the authorities to apprehend those responsible.
''Lazio fans have shown in recent times they have totally abandoned manifestations of cowardly and free physical violence, as were those that occurred last night," the statement read.
"Lazio have always preached to its supporters to show sportsmanship and be chivalrous towards opponents and their fans, limiting their utterances to healthy sporting rivalry, as evidenced by the behavior of the fans at the stadium in the recent derby vs Roma of last week.
"Events like those that occurred last night have nothing to do with football and its manifestations and are an expression of pure criminality, against whom the police and the judiciary must intervene with all the tools at their disposal.
"Lazio hopes that the perpetrators of the facts are identified as soon as possible and punished in a fair way, thus moving unfair suspicions away from their supporters."