Lee Johnson leapt to the defence of Famara Diedhiou after his substitute had marred a thrilling Championship win with an 86th minute red card.
Charlton took a 65th-minute lead when City goalkeeper Dan Bentley advanced to the corner of his penalty area only to be beaten to the ball by Macauley Bonne, who coolly slotted into an empty net.
Diedhiou levelled 10 minutes later, nodding home from close range after fellow replacement Rodri had headed on a right-wing cross, but was then dismissed for kicking out at Jason Pearce following a challenge by the centre-back.
It mattered little as Josh Brownhill produced a lung-bursting run deep into eight minutes of stoppage time to control Kasey Palmer's through ball and fire past the impressive Dillon Phillips.
The Diedhiou incident provoked a melee involving numerous players from both sides, but head coach Johnson insisted things were not as they seemed.
He said: "Famara was going for the ball 100 per cent. Their lad was on the ground protecting it and as Fam went to win possession the referee's whistle went, which made it seem worse than it was.
"The communication between the officials was unbelievable. Only the fourth official saw it as a sending-off. We could hear him saying: "red, red, red over the microphone.
"It is difficult to overturn dismissals like that one without VAR. I will look at it again and then decide whether we should appeal.
"I'm frustrated that it spoiled a huge win for us. I am so proud of my players because that team we put out tonight was nothing like the one I envisaged before the season started.
"We have had so many injuries and the lads who have come in are doing brilliantly. Some of the them are young and learning, but they keep going for 90 minutes plus."
Charlton lost Sam Field and Jake Forster-Caskey to first-half injuries, but boss Lee Bowyer, watching from the stands while serving a touchline ban, rightly insisted: "The least we deserved was a draw.
"We were the better side for 60 minutes, but if one thing let us down we were not ruthless enough.
"We should have put the game to bed by the hour. I was down in the dressing room when they scored the winner and just heard the roar.
"I really felt for the lads because we had come to a very good side and been better than them for long periods, despite the injuries.
"Sam Field has suffered a knee problem, which doesn't look good. Having used all three subs, we probably tired a bit in the closing stages, but I couldn't have asked for more.
"Having got into plenty of good positions, we couldn't quite come up with the final pass or finish. The players are learning with every Championship game and this was a harsh lesson.
"I have told the lads how pleased I am with them and we will go again."