Former England winger John Salako came off the bench to finish off Portsmouth and keep Charlton flying high at the top of the table.
Salako, who is on a short-term contract at The Valley, sealed the win for Alan Curbishley's men when he cashed in on anther farcical mix-up in the Portsmouth defence in the dying minutes.
Pompey left the field to a torrent of boos from fans who have now seen them plunge further into trouble after four successive defeats.
It had looked as if Portsmouth's former Charlton goalkeeper Andy Pettersen would ruin his old team-mates afternoon.
Petterson, who left the Addicks on a free transfer in the summer, reacted quickly after 16 minutes to push away a shot from John Robinson after the winger had created himself an opening.
Portsmouth's best chance fell to Michael Panopoulus but he was denied by Charlton keeper Dean Kiely.
Opposite number Petterson, however, was at fault when Charlton took the lead just before half-time. He could only parry a shot from Andy Hunt and Robinson followed up to score.
In the second half Petterson found himself under siege.
He first denied Clive Mendonca from close range before spectacularly pushing over a drive from Newton.
He then excelled again clawing away a curling shot from Robinson.
Portsmouth were reduced to 10 men when, having used all three substitutes, they lost Stefani Miglioranzi with an injury.
It was all too much for them and amid chaos Salako took advantage to finish Pompey off.