Neil Lennon and the Scottish Football Association are on course for yet another collision after the Celtic manager described his sending off at half-time at Ibrox as "a joke" and claimed he was "deprived of doing my job properly" during the 3-2 defeat to Rangers.
Celtic were odds-on to get the win required to clinch the Clydesdale Bank Premier League title, but Light Blues midfielder Sone Aluko scored a marvellous solo goal in the 11th minute to spark another afternoon of Old Firm drama.
Lennon was raging when Hoops defender Cha Du-ri was sent off by referee Calum Murray in the 28th minute for a challenge on Lee Wallace. The Parkhead boss spoke to Murray going up the tunnel and was then called into the official's room where he was sent to the stand, although he said he had to watch the second half from the media room "for my own safety".
Celtic midfielder Victor Wanyama was sent off for a two-footed tackle on Steven Whittaker before goals from substitute Andy Little and Wallace put Rangers 3-0 ahead, with a Scott Brown penalty and a Thomas Rogne injury-time header reducing the deficit - but not the ire of the Parkhead manager.
Lennon, who has been asked by the SFA's compliance officer, Vincent Lunny, for an explanation of his criticism of referee Willie Collum following last week's 1-0 Scottish Communities League Cup final against Kilmarnock at Hampden, said: "The first one is not a sending off and the second is borderline probably, you can't tackle like that. My sending off is joke. I don't think I deserved to be sent off. My staff are very angry about it, my players are angry and disappointed.
"I spoke quite quietly and coldly to the referee in the tunnel. I didn't swear and didn't point any fingers. I told him I wasn't happy with his first-half performance. I was speaking to the match delegate after the game and their version of events are different from mine but I've got witnesses to back me up."