Celtic fans raised an anti-fascist banner in response to Lazio supporters giving fascist salutes outside the ground and inside Celtic Park as the two teams clashed in the Europa League last night.
That the Serie A side has a section of right-wing sympathetic supporters has not gone unnoticed in the lead-up to the Group E fixture, with the behaviour of some of those fans leading to a partial stadium closure when Celtic travel to Rome for the return meeting.
Despite pleas from the Biancocelesti hierarchy for fans not to give the "Roman Salute", a number of travelling supporters were seen making the gesture on the way to the stadium, outside the ground and during the match.
One section of home supporters held up anti-fascist banners while another group in the area of the stadium that houses the club's "ultra" fans group, the Green Brigade, held up a banner depicting the death by hanging of former Italian Prime Minister and fascist leader Benito Mussolini with the slogan "Follow your leader."
Football fans from around the globe took to social media to praise the Celtic fans for their actions.
However, the Hoops are likely to face sanctions from UEFA for the umpteenth time as European football's governing body takes a dim view of what it deems as "political banners".
Article 16, section 2 of the UEFA Disciplinary Regulations 2019 states: "All associations and clubs are liable for the following inappropriate behaviour on the part of their supporters and may be subject to disciplinary measures and directives even if they can prove the absence of any negligence in relation to the organisation of the match"
"the use of gestures, words, objects or any other means to transmit a provocative message that is not fit for a sports event, particularly provocative messages that are of a political, ideological, religious or offensive nature."
Celtic could also face retrospective action for a banner raised by the Green Brigade which appeared to have been based on the logo of a left-wing terrorist organisation, active in the 1970s and 1980s and responsible for the kidnap and murder of a former Italian prime minister.
The group's "Brigate Verde" banner was obviously a play on "Green Brigade[s]" but the symbol accompanying the words was effectively a white and green version of the Brigate Rosse logo.
Lazio are also likely to face further punishment if their fans are found to have made fascist salutes during the match.