Celtic face a hefty punishment after UEFA opened disciplinary proceedings following the pitch invasion by a fan during the Champions League defeat to Paris St Germain.
A supporter ran onto the pitch to confront Kylian Mbappe and appeared to aim a kick at the French striker.
UEFA have already fined Celtic 11 times in less than six years over fan behaviour issues ranging from pro-IRA chants to fireworks, crowd disturbances and illicit banners.
There are fears they could now be forced to play upcoming home matches with a partial stadium closure or at worst case, behind-closed-doors.
PSG, who ran out 5-0 winners in the opening group stage encounter, have also been charged for ripping seats out of the away end.
Celtic fan ran on the pitch and aimed a kick at Kylian Mbappe (Image: Getty Images Europe)
A fan is led off after running on the pitch (Image: PA)
Boss Brendan Rodgers expressed his disappointment at the incident: “The crowd reaction said it all.
“It is disappointing at any ground that a supporter gets on to the pitch.
“I am sure the club will deal with that. It shouldn’t be anything that we should see on a football field. The crowd in their reaction told you everything you need to know.”
Brendan Rodgers walks off dejected
The fan is believed to be from the Portadown area of Armagh in Northern Ireland.
With Celtic trailing 3-0 approaching the interval of the Group B encounter, play was halted as an individual broke through the cordons and onto the playing surface.
Having run half the length of the pitch unchallenged, the culprit moved in the direction of a startled Mbappe and swung a leg.
Police and stewards quickly then hauled the invader from the field and he faced the fury of the fans in the stands as he was led away.