Charlton lost another game they could easily have won at the Abax Stadium on Saturday afternoon.
Two late goals were enough to give Peterborough the spoils, after the Addicks had the better of things for much of the game.
Karl Robinson had Jason Pearce and Josh Magennis available again, and the pair took their places on the bench.
Robinson played a diamond formation in midfield again, with Johnnie Jackson at the base, Ricky Holmes at the tip, and Frederik Ulvestad and Jake Forster-Caskey in the middle.
The front duo – Lee Novak and Tony Watt – carried knocks into the game. Novak had a groin problem, and Watt only passed a fitness test on his injured ankle on Saturday morning.
Both had to be replaced during the course of the game.
Novak, Forster-Caskey and Holmes all had first half chances. Novak had the best chance, but was foiled by Luke McGee when he was faced with a one-on-one situation.
Posh took the lead fourteen minutes from time. Marcus Maddison’s right-wing cross was met at the far post by Martin Samuelsen. The West Ham loanee had only been on the pitch for two minutes.
Peterborough took a firm grip on the game after that, and it was no surprise when they added a second eight minutes later.
Maddison’s exquisite chip from the edge of the went in off the underside of the bar.
Charlton are now just four points above the relegation zone, and Robinson will be desperate to win Tuesday’s encounter with MK Dons.
Charlton: Rudd, Byrne, Teixeira, Bauer, Chicksen; Jackson (Crofts 68), Ulvestad, Forster-Caskey, Holmes; Watt (Magennis 68), Novak (Botaka 74).
Subs: Phillips, Pearce, Aribo, Dasilva.
Booked: Byrne 66 (foul), Bauer 90 (foul).
Peterborough: McGee, Smith, Bostwick, Baldwin, Binnom-Williams (Hughes 77); Maddison, Da Silva Lopes, Forrester (Samuelsen 74), Grant; Nichols (Mackail-Smith 61), Morias.
Subs: Tyler, Inman, Chettle, Borg.
Goals: Samuelson 76, Maddison 84.
Booked: Morias 90 (dissent).
Referee: Graham Salisbury (Lancashire).
Attn: 5,482 (716 Charlton).
TAGS: Charlton Athletic