Charlton were left to rue a missed penalty by Karlan Grant as they had to settle for a point at London Road.
Grant was denied from the spot by home goalkeeper Conor O’Malley with just twelve minutes as they were unable to turn second-half dominance into a winning goal.
The game between two of League One’s promotion hopefuls ended goalless.
The hosts had Charlton pinned into their own half in the opening stages but had just a handful of hopeful efforts to show for it. Ivan Toney was first to chance his arm, acrobatically volleying at goal after a cross deflected off Josh Cullen, although it proved easy for stopper Dillon Phillips.
Former Stevenage man Matt Godden saw a header and then a volley fly off-target for the home side, before Lee Bowyer’s side started to gain a foothold in the contest.
West Ham loanee Josh Cullen’s corner nearly curled straight in at the near-post, only to be headed behind by an alert defender. The young midfielder then latched onto Grant’s deep cross, with keeper Conor O’Malley tipping over as his volley looked set to drift in just under the crossbar.
Ben Reeves lifted an effort over the bar and Jonny Williams was booked for simulation after going to ground inside the Posh box, before the home side started forced a succession of corner kicks that Phillips did well to punch away.
Phillips was called into action once more as he spread himself well to block Daniel Lafferty’s cross, before Grant saw a half-volleyed effort hacked away at the other end in added time at the end of the first-period.
Steve Evans’ side should have edged ahead thirty seconds after the break. Toney squared a dropping ball for Godden, who could only flash wide from six yards out.
The Addicks came even closer a minute later. Grant collected the ball on the left-hand-side before cutting in and seeing his drive deflect into the air. The ball looped over the stranded O’Malley but bounced onto the crossbar and out.
Darren Pratley saw a diving header drift just wide of the far-post after great work from Ben Reeves on the left to set him up with a cross.
Bowyer threw Reeco Hackett-Fairchild into the mix with a quarter of the game to go as he looked for a way to break the deadlock, with Pratley making way.
Phillips dived well to his left to tip a long-range drive from Daniel Lafferty around the post, before Reeves side-footed just wide from 18 yards for the South Londoners.
Grant blew a massive opportunity to win it for the Addicks with twelve minutes left. Cuilen was felled just inside the Posh penalty area, but O’Malley guessed the right way to save Grant’s tame spot-kick.
The academy graduate was then unable to add a telling touch to a low-cross moments later, as the Addicks had to settle for just a point.