Neil Lennon's relationship with the Scottish Football Association could be heading towards an irretrievable breakdown after he criticised referee Euan Norris for awarding the late penalty which led to the Hoops' 2-1 Scottish Cup semi-final defeat by Hearts and claimed: "It's personal.''
• Celtic blog: Is it personal with Lennon?
Lennon marched onto the pitch to confront Norris after the Premier League champions' hopes of a league and cup double were sunk from the spot by substitute Craig Beattie, after a penalty was given when a shot from Jambos skipper Marius Zaliukas hit the arm of Hoops midfielder Joe Ledley.
Lennon, who has three disciplinary cases pending, was further enraged when Norris refused Celtic a penalty in injury time when the ball appeared to come off the arm of Hearts defender Andy Webster.
He did not attend the post-match press conference, where his place taken by coach Alan Thompson who confirmed Lennon had been to the referee's room and it is likely that he will be asked to explain his actions.
The Northern Irishman will almost certainly be in more trouble after a comment made on his Twitter account.
Lennon tweeted: "Referee told players he thought (Victor) Wanyama handled ... feel so sorry for players and fans ... I think it's personal myself.''
He left himself open to further and perhaps more serious sanctions when he later re-tweeted a comment from Celtic supporter @DazDiCanio which suggested the club "pack our bags and get out of this league that is run by crooked £SFA officials''.
The game had looked to be heading to extra-time when Celtic striker Gary Hooper levelled Rudi Skacel's opener with four minutes remaining.
However, Beattie's winner against his former club ensured Hearts will play Hibernian in the final of the Scottish Cup for the first time since 1896, with the Leith side looking to win the trophy for the first time since 1902.
Lennon was written to by SFA compliance officer Vincent Lunny demanding an explanation for his comments about referees ahead of an SPL game against St Johnstone at Celtic Park at the start of the month.
The Parkhead boss is fighting two other charges relating to criticism of referee Willie Collum after the League Cup final defeat to Kilmarnock and his half-time dismissal by referee Calum Murray during the recent 3-2 SPL defeat at Ibrox.
Hugh Dallas believes Celtic manager Neil Lennon went too too far to "bully'' Norris.
"I can't remember in 25 years of refereeing seeing a manager run that far onto a pitch to bully a referee,'' Dallas told STV. "These pictures are going around the world and it is not good.
"Take another example yesterday in the Tottenham Hotspur game. It was a huge occasion and a goal was given where the ball didn't cross the line. After the game, Harry Redknapp said he had a chat with the referee, who admitted he made an honest mistake.
"Redknapp said he was disappointed but was keen to move on. That's how we should do it in Scotland.''