New signing Martin Pringle snatched a vital point for Charlton with the last kick of the game at The Valley - seconds after the home side had an equaliser controversially ruled out.
Temuri Ketsbaia gave the visitors the lead after 14 minutes when he latched on to Alan Shearer's flick-on before firing past Simon Royce from 25 yards.
Nolberto Solano then doubled the advantage on 55 minutes after more good work by Shearer and Ketsbaia, the Peruvian stabbing home the loose ball after Ketsbaia's shot was only partially saved by Royce.
Charlton looked dead and buried, but an inspired substitution brought them back into the game, and Mark Bright scored with his first touch seconds after coming on.
The home crowd then thought they had ended their run of eight straight league defeats when another Bright header looked to have crossed the line before being hacked clear.
Referee Peter Jones and his linesman weren't convinced however - they will be when they see a video replay of the incident - and it looked as though Newcastle, down to 10 men after the dismissal of Nikos Dabizas, would escape.
But there was still time for another dramatic twist as Swedish international Pringle, making his home debut since joining on loan from Benfica, fired a volley past Harper with the last kick of the game to spark wild celebrations.
The home side had started brightly with Keith Jones, replacing the suspended Neil Redfearn, battling his way to the byline. But Steve Harper, deputising for the suspended Shay Given, reacted quickly to cut out the danger.
John Robinson then went close to breaking the deadlock after seven minutes, volleying just over from Pringle's flick-on.
But Newcastle gradually began to get into the game, and Gary Speed fired inches wide after Ketsbaia's lay-off 20 yards out. Shearer then escaped the attentions of Carl Tiler to race to the byline and Mills did well to get to the cross before the lurking Ketsbaia.
The visitors took the lead after 14 minutes with a breakaway goal. Warren Barton's long clearance was neatly headed into the path of Ketsbaia by Shearer but at that stage there appeared little on.
Shearer peeled off to the right and was screaming for the return pass when the Georgian kept advancing as the Charlton defence backed off, before unleashing a low right-foot shot past Royce, making his Premiership debut, into the bottom corner.
Shearer was booked for a foul on Pringle, though the England captain vigorously protested that he had played the ball. The caution will earn him a one-match ban.
The second half was only a few seconds old when Dabizas joined Shearer in referee Jones' notebook for a foul on Andy Hunt, but Charlton failed to take advantage of the resulting free-kick.
The home side enjoyed a brief spell of pressure but were unable to find the final quality ball and were soon made to pay the price.
Shearer was again the supplier with another deft flick on to Ketsbaia who beat Mills before firing at Royce. The goalkeeper appeared to have it covered but it squirmed under his body and Solano was on hand to stab in the loose ball.
That prompted a do-or-die double substitution from manager Alan Curbishley on 62 minutes, and the switch paid instant dividends. Mills' long throw was flicked on by Youds to 36-yearold Bright, on for the injured Andy Hunt, and he scored with a downward header, his first touch of the ball on his first league appearance this season.
Newcastle were reduced to 10 men after 77 minutes when Dabizas was sent off for a second bookable offence after a foul on Mark Kinsella.
Charlton Athletic: Royce, Mills, Powell, Youds, Newton (Konchesky 63), Kinsella, Hunt (Bright 63), Robinson, Jones (Parker 79), Tiler, Pringle. Subs Not Used: Ilic, Brown. Goals: Bright 64, Pringle 90.
Newcastle United: Harper, Barton, Howey, Shearer, Speed, Ketsbaia (Dalglish 89), Georgiadis, Solano (Hughes 79), Domi, Dabizas, Brady (Charvet 72). Subs Not Used: Perez, Barnes. Sent Off: Dabizas (77). Booked: Shearer, Dabizas, Georgiadis. Goals: Ketsbaia 13, Solano 55.
Referee: P Jones (Loughborough).
