Jose Mourinho could be set for a heavy punishment after pinching the nose of Galatasaray boss Okan Buruk following a chaotic Istanbul derby on Wednesday.
Mourinho's Fenerbahce were knocked out of the Turkish Cup by their bitter rivals after slipping to a 2-1 defeat, but the game was overshadowed by Mourinho confronting Buruk on the pitch after the final whistle.
The former Chelsea, Manchester United and Tottenham manager was seen pinching Buruk's nose, with his opposite number subsequently falling to the floor clutching his face.
The incident sparked a mass brawl, with three players - Fenerbahce's Mert Yandas and Galatasaray's Kerem Demirbay and Baris Yilmaz - sent off.
Mourinho must now wait to see whether he will be sanctioned for his behaviour, and official regulations suggest he may be in line for a lengthy ban.
According to the Football Disciplinary Regulations, Mourinho is likely to receive a 1-3 match ban if the nose-pinching action is deemed to be 'unsportsmanlike conduct'.
However, if Mourinho's behaviour is viewed as 'assault', the Football Disciplinary Board recommends a 5-10 match ban or a 45-90 day suspension.
Fenerbahce have nine league games remaining, meaning Mourinho could miss the rest of the season if he is handed a more significant penalty.
This would be a big blow for Fenerbahce, who are currently trying to chase down league leaders Galatasaray.
Galatasaray have a six-point lead at the top of the table, but have played a game more than Mourinho's men.
The rivalry between the two teams has only ramped up in recent months, and Mourinho has been at the centre of it all.
The 62-year-old Portuguese manager filed a lawsuit against Galatasaray in February after the club accused him of making racist statements.
Mourinho, speaking after a 0-0 draw in the Istanbul derby, said the Galatasaray bench had been 'jumping like monkeys' when appealing for refereeing decisions to go in their favour.
Mourinho was subsequently backed by multiple black players that he had previously managed, including ex-Chelsea stars Didier Drogba and Michael Essien, and he defended himself in an interview with Sky Sports as he insisted Galatasaray had twisted his words.
The bad blood only intensified after Wednesday's cup match as Galatasaray posted a mocking video on social media of a cartoon version of Mourinho complaining and crying about losing to them before waking up in a psychiatric ward.