Caolan Boyd-Munce equalised with virtually the last kick of the first-half for Blues, cancelling out Alfie Doughty's 22nd minute strike.
Both Aitor Karanka and Lee Bowyer played different sides in either half, mixing up their first team squads.
Both Lukas Jutkiewicz and Gary Gardner sat out proceedings.
Blues started off with Odin Bailey playing off Jayden Reid in a 4-2-3-1 with second year scholar, Amari Miller, 17, occupying a wide berth on the left.
Blues had to stave off an early alarm, with Geraldo Bajrami covering round to stop a dangerous break into the box by the Addicks.
And Zach Jeacock's first real involvement came when a dangerous cross from the left by Doughty was touched behind, at full stretch, by the England Under-19 international.
The visitors took the lead following a nice give-and-go move, that saw George Lapslie burst into the right-hand side of the area and cross for Doughty to slide into the roof of the net.
Blues response was good, with the sharp and lively Bailey to the fore.
Kristian Pedersen made ground down the left and fed Bailey, whose low left foot shot whizzed just past the post.
Dan Crowley sent over an inviting, dangerous cross following a feed from Bailey, but no one could quite get a vital touch on it right in front of goal.
Then Miller, all full of eager teen intent, drove down the middle towards the edge of the box only to fire high over the crossbar.
Charlton, in the first-half, were content to sit in their shape and let Blues try and open them up.
And that's what happened, eventually, in the 45th minute, after Marc Roberts nipped in to intercept a pass in midfield and prodded the ball forward.
Although it seemed intended for Reid, the ball ran on to the side of the striker in behind last man Lapslie, and Boyd-Munce was alive to the possibilities.
He was swift to get onto it, held off the attempt to foul as he went through, and slotted the ball neatly into the bottom corner with his sidefoot.
After the break, the action seemed a little more frenetic and abrasive, from both teams.
George Friend started alongside Harlee Dean, and Josh Dacres-Cogley, Steve Seddon and Charlie Lakin were back in action in Blues shirts.
It was Lakin, who was vibrant throughout, who went close early into the period when he chased after a deflected Jeremie Bela cross that looped up and got his studs on it, directing it not too far wide of the post.
In the 69th minute, Dean got in a vital block on a Josh Davison attempt in the heart of the area after a cross dropped kindly to him on the wind.
Then Blues went close to scoring as Bela and Adan George swapped passes on the left; Bela went in at goal from a tight angle and fired a fierce near post shot that Dillion Phillips, standing big, blocked with his chest.
The action swung to the other end and Ben Purrington headed just wide from a corner before Jeacock made a good save, gathering and keeping hold of a difficult low shot from outside the area by a Charlton trialist.
With two minutes left Blues might have nabbed the winner, through Lakin.
After more aggressive work in a midfield skirmish, Blues won possession and sent him away. Lakin cut inside onto his right foot and punted at goal from the edge of the area, his shot only just clearing the angle of post and crossbar.
Blues (first-half): Jeacock, Colin, Pedersen, Bajrami, Roberts, Sunjic, Boyd-Munce, Crowley, Bailey, Miller, Reid.
Blues (second-half): Jeacock, Dacres-Cogley, Seddon, Dean, Friend, Davis, Kieftenbeld, Bela, Medina, Lakin, George.
Not used: Clayton, Brooks.