City's triumph in the Champions League quarter-final descended into chaos as a mass brawl between the players spilled into the tunnel after full-time.
Stefan Savic was the villain of the piece, dragging Phil Foden from the pitch, headbutting Raheem Sterling and then pursuing Jack Grealish to the changing room after pulling his hair.
But Carson, the former Derby man, emerged as an unsung hero.
Police were on the scene as an animated Sime Vrsaljko acted like he wanted to take on the entire City squad - despite very little stopping him from actually doing so - after some fisticuffs with Carson and Kyle Walker.
However, the Atletico full-back wasn't fooling Carson. The veteran goalkeeper has no time for handbags at dawn.
Having made two appearances for City during his time at the club, it turns out Carson also acts as a bouncer for his teammates.
Fans on social media spotted a moment in the tunnel footage when the 36-year-old, an unused substitute on the night, appeared to offer out Vrsaljko, gesturing at him to take the dispute 'outside', as it were.
And Carson will no doubt have the last laugh after finding himself in yet another Champions League semi-final squad.
That's three for his career: one more than both Arsenal and Tottenham.