Charlton were punished for wasting several chances after AFC Wimbledon scored two late goals to win 2-1 at the Valley.
Dominic Poleon and substitute Tyrone Barnett's strikes cancelled Ademola Lookman eighth-minute goal.
The victory was Wimbledon's second of the campaign and ended Charlton's six-game unbeaten run.
The Addicks took the lead when Lookman cut in from the left and struck the ball past James Shea from 20 yards.
And Lookman continued to shine when he worked his way into the box and saw his powerful drive pushed away from goal just before the break.
Ricky Holmes could have doubled Charlton's lead in the 54th minute but his close-range effort was excellently saved by Shea.
Holmes and Nicky Ajose wasted good opportunities to put the game to bed for Charlton.
It was Poleon's trickery which brought about the Dons' equaliser in the 78th minute when he beat two players in the box and slotted the ball home.
It got worse for Charlton just seven minutes later as Barry Fuller's cross was emphatically headed in by Barnett.