An apparent handshake snub involving Kyle Walker and a former Manchester City coach sparked the dramatic tunnel bust-up which followed Arsenal's late win at the Emirates on Sunday.
Sky Sports video footage showed City defender Walker and team-mate Erling Haaland walking off the field after Gabriel Martinelli's 86th-minute goal inflicted their second successive league loss.
Nicolas Jover, the Arsenal set-piece coach who worked in the same role for Pep Guardiola at City between 2019 and 2021, is seen offering a handshake to Walker but is dismissed.
Berlin-born Jover, 41, began his career in the game as a video analyst at French club Montpellier and briefly served in a similar role for the Croatia national team.
He came to England in July 2016 to work as an assistant coach to Dean Smith at Brentford and continued under Thomas Frank when the Bees were in the Championship.
His talents were recognised by Guardiola and in 2019, Jover joined City's coaching staff to work on set-pieces.
While at the Etihad, Jover worked in his first few months with Mikel Arteta, Guardiola's No 2, before he left to take the Arsenal job.
Arteta persuaded Jover to take a similar role at Arsenal in July 2021 after previous set-piece coach Andreas Georgson returned to Malmo as sporting director.
Jover established a reputation for set-piece innovation - during his two years with City, the club created 104 chances from set plays in Premier League action, leading to 16 goals.
He also improved City's record of defending opposition set-pieces, helping them reduce the percentage of goals conceded from such situation from 39 per cent in 2018-19 to just 20 per cent the following season and 19 per cent the season after.
Arsenal's set-piece effectiveness showed a similar improvement once Jover was installed at the club.
Sky footage showed how Walker dismissed Jover with several waves of his hand and continues walking towards the tunnel after the final whistle.
However, after words are exchanged, Walker turns back and directly confronts Jover with the pair practically face-to-face as they continue their row.
Haaland also turns around to back Walker up before the situation quickly escalates with coaches from both teams - as well as several other City players - becoming involved.
A clearly agitated Walker continues to argue until he is eventually persuaded down the tunnel, pointing his finger in the face of an Arsenal official at one stage.
Another camera angle showed Jover wagging his finger at nobody in particular while being calmed by Bukayo Saka.
Guardiola refuses to elaborate on what caused the bust-up afterwards, saying: 'I know what happened but I won't say anything. They know it.'
Martinelli's deflected winner ended Arsenal's 12-match losing streak in Premier League encounters against City.
It means City have lost three of their last four matches in an unusual blip for Guardiola's side.
They were knocked out of the Carabao Cup by Newcastle United, then went down 2-1 to Wolves in the league at Molineux.
They recovered with a 3-1 Champions League win away to RB Leipzig in midweek but then suffered Sunday's defeat in north London as we enter the international fortnight.
Arsenal boss Arteta insisted after the game that he had not seen the altercation.
Former Manchester City defender Micah Richards said: 'It looked like he was going to shake his hand, but Kyle didn't really want to,
'We're in October, if we were in March or April I could understand the frustration, they probably don't want to go to Arsenal and lose but it's not the end of the world.'
Ex-Arsenal winger Theo Walcott, also working for Sky, said a 'nerve had been hit' in the post-match fracas.
'We always look at City and they've been very professional and not reacting in situations,' he added.
'And that's where I feel like a nerve's been hit here, and he's caught it there definitely.'