The Premier League champions booked their passage into the semi-final of the Champions League after a goalless draw at the Wanda Metropolitano on Wednesday evening, having taken a 1-0 first-leg lead to the Spanish capital.
But the match was overshadowed in the dying embers of the game when Atletico instigated a massive melee which continued into the tunnel.
Phil Foden was fouled by Felipe but Stefan Savic felt the England international was milking it and screamed in his face before trying to drag him up off the ground, prompting other City players to rush over and defend their teammate.
Savic then squared up to Raheem Sterling, butting his head into the City man, before grabbing Jack Grealish’s hair and pulling it – with the two players continuing their confrontation at the tunnel entrance after the match.
But they were not the only players to be involved in a post-match scuffle, with Vrsaljko – who was an unused substitute in the match – trying to pick a fight with half the City team.
French broadcaster RMC Sport aired footage from the tunnel which shows Grealish and Savic continuing their war of words before an even bigger brawl threatens to kick off behind them.
At the tunnel entrance, Vrsaljko initially appeared to be arguing with members of City’s playing staff and was being held back by an Atletico Madrid official.
Things then turned very ugly when he chucked his substitute’s bib at the City players and staff, which included Aymeric Laporte and Ilkay Gundogan, and that prompted Walker – who had been further back – to run over and get involved.
It was not clear who Vrsaljko was originally directing his ire at, but suddenly he was focused only on Walker and managed to wrestle free of the officials and staff holding him back and made a bizarre lunge towards Walker as if to try and headbutt him – even though they were several feet apart.
The City defender was held back and then dragged away by a combination of Laporte and Ederson as Vrsaljko tried to break free of the teammates holding him back to get at Walker again, though eventually he was restrained.
All players were eventually led to their respective dressing rooms, with a police presence required in the tunnel, and Atletico are expected to face a hefty fine from UEFA for their antics.
For more stories like this, check our sport page.