With both clubs eliminated from the Carling Cup by Premier League opponents in midweek, there were few clear cut chances before the game came to life with two goals in as many minutes.
Posh, beaten at Blackburn on Tuesday, grabbed a 24th minute advantage from the penalty spot with George Boyd sending Barnsley's Luke Steele wrong way.
It was Boyd's tenth goal of the campaign and the spot-kick came when Darren Moore pulled down Gaby Zakuani as a Boyd corner came over.
Posh celebrations had hardly subsided before Mark Robins' hard-working Tykes side were level, Bogdanovic forcing in a header from just a couple of yards after Macken's far-post cross beat teenage 'keeper Ben Amos, making a debut on loan from Manchester United in place of the suspended Joe Lewis.
Chris Whelpdale limped off to be replaced in the home attack by Danny Rose on 38 minutes and he hadn't touched the ball before Barnsley took the lead a minute later.
Posh defender Darren Morgan slipped as he tried to reach Anderson da Silva's searching pass to give Macken a clear run on goal before he left Amos, who was on the bench when United won at Barnsley on Tuesday, completely helpless with a fierce rising shot.
Posh pressed hard for an equaliser after the break with Shaun Batt's pace on the right causing Barnsley plenty of problems, the former Fisher wideman following up a succession of dangerous crosses with a low shot that flashed just wide of Steele's far upright.
Then Ryan Shotton cleared a Morgan header from the Barnsley goal-line with Steele beaten following a Boyd corner.
But that was as close as Posh got, shattering manager Darren Ferguson's hopes of back to back home wins and Macken even had an added time effort ruled out for offside.