Andre Villas-Boas has urged UEFA to take action against Lazio if their fans are found guilty of anti-Semitic chanting at Tottenham Hotspur during Thursday's Europa League draw at the Stadio Olimpico.
UEFA fined Lazio £32,500 for their fans' monkey chanting at three Spurs players during the reverse fixture in September, and Villas-Boas hopes the organisation moves swiftly to establish the facts.
"It will take another investigation," the Tottenham manager told a press conference. "It happened last time and it was acted upon quickly by UEFA. We will have to wait and see if there is anything to act upon. If there is UEFA have to act."
UEFA is expected to decide whether to launch an investigation on Friday when the match delegate's report is received.
Thursday night's game had already been overshadowed prior to kick-off by a brutal attack on a group of Tottenham's supporters in the early hours of the morning.
The fans were attacked in the Drunken Sailor pub in Campo dei Fiori at around 1am local time and were beaten with sticks and glass bottles. One fan is recovering in hospital after being stabbed in the head and leg.
Villas-Boas expressed his disappointment at the attack, saying: "It is an extremely difficult moment for them. We have to be aware there is a police investigation and I'm not in control of all facts. But there is massive disappointment and the fear they've gone through is hard.
"To point a finger at this point would be incorrect but (we) give them a message of support. As a club, we will try to help them overcome this."
Lazio's notorious 'Ultras' fanbase have been blamed for the attack, but club president Claudio Lotito has denied such allegations, claiming instead "foreigners" were to blame.
"Lazio fans had nothing to do with what happened last night in Campo de Fiori," he said. "When it emerges who was really responsible, some people will be surprised. It is all too easy to speak about aggression from people whose faces are covered and say that they are Lazio fans.
"This isn't the case. Do you know, for example, that among these criminals, who must be punished in a harsh manner, there were also three foreigners (ie non-Italians)? I maintain that Lazio fans had nothing to do with it."
Information from Press Association was used in this report.