A much-changed City XI were on the wrong end of a scoreline not reflecting their efforts on their npower Championship farewell in East London.
Goalless at the interval, a brace from Yann Kermogant and further goals from Jonathan Obika and Johnnie Jackson flattered the hosts, who were pegged back to 2-1 courtesy of Bobby Reid’s first professional goal just before the hour.
At that point City were on top, but two goals in the final 11 minutes called an abrupt halt to their hopes of a comeback.
Young duo Joe Bryan and Reid were both handed starts having returned from loan spells with Plymouth and Oldham respectively, in a line-up which included six new faces from those who started the 3-1 home defeat to Huddersfield Town last time out.
Louis Carey, Liam Fontaine, Paul Anderson and Ryan Taylor were also drafted in, while Richard Foster, Matthew Bates, Liam Kelly, Marvin Elliott, Albert Adomah
and Steven Davies all missed out.
It was a bright start for the hosts, last year’s League One champions, as Callum Harriott’s cross was glanced just wide by Obika in the opening seconds.
City were nearly undone by another cross soon after when Kermogant headed a Mark Gower corner inches off target with Tom Heaton no more than a spectator.
In truth it was a first half with an end of season waft in the air for the most part, although you sensed Neil Kilkenny and Reid – starting a first team game for the very first time – were enjoying such time and space in midfield.
But chances remained at a premium for the visitors. At the other end, the lively Harriott smelled blood when one-on-one with Carey, almost double his age, but the veteran stood his ground to force the young pretender into a wayward shot.
All in all it had been rather forgettable stuff, but Kermogant’s exquisite finish soon brought The Valley to its feet, as the big Frenchman converted Gower’s right-wing cross with a rising volley that flew past Heaton into the top corner from 15 yards.
No sooner had City conceded were they were two down thanks to the same man. Chris Solly only just kept the ball in for the Addicks on the byeline, but his left-footed cross on the run was inch-perfect for Kermogant, who towered above the white shirts to send a thunderous header into the roof of the net.
Sean O’Driscoll responded by introducing Adomah for Sam Baldock, and the Ghanaian was quick to make an impression, crossing from the left towards Reid who met the ball at the penalty spot but saw his header drift wide of the far post.
But the 20-year-old’s big moment would come. A mistake at the back from Michael Morrison left Reid with a clear run on goal, and one touch later he was on the edge of the ‘D’ of the penalty area with David Button advancing from the Charlton goal.
Unflustered, the local Academy product lifted his head and dispatched the bouncing ball with a perfectly weighted lob over the former Tottenham Hotspur goalkeeper, who backpedalled furiously only to see the ball drop into the net just underneath his crossbar.
Suddenly City were playing with a real purpose. Reid tried his luck twice more from distance – firstly high and wide, secondly into the grateful arms of the stooping Button.
Adomah had certainly made an impact too, although he would have been disappointed to scuff a decent chance wide after a clever flick in behind the defence from Taylor.
But the winger was still as enthusiastic and willing as ever, showing Solly a clean pair of heels down the City right. When his eventual cross was hampered by a tug from behind, referee Carl Berry brought the play back for a free kick.
One from the training ground was what followed, but Carey was unable to repeat his heroics in a similar part of the world from five years prior, as he skewed Kilkenny’s pull-back off target – more Wimbledon Common than Selhurst Park, it must be said.
City were pressing hard for an equaliser, but Charlton’s habit of losing leads at home would not rear its ugly head thanks to Obika’s simple third after Kermogant’s sublime chip bounced out off the crossbar.
Jackson then got in on the act himself at the end of a slick counter-attack five minutes from time, while Chris Powell’s side even threatened a fifth in the closing stages.
But four in itself was harsh on City, who matched their hosts for long periods and were unfortunate to bow out of the second tier on the receiving end of such a loss.