AFC Wimbledon had only Tom Elliott's soaring header in the first half to show for their labours - but that was enough.
In truth, if had they won 6-0, no one at Peterborough could have complained as keeper James Shea had one of his easier games between the sticks.
Only towards the end was he called on to earn his pay, while at the other end the chances that got away were longer than a fisherman's bad-luck story.
Elliott picked up from where he Dons left off on Tuesday by scoring early doors.
In football terms, time between the winner at Bury and this one was a mere 11 minutes - thanks to Elliott's header at the back post as his desire and height outjumped the Posh defence to nod home.
Will Nightingale then had an effort cleared off line before Chris Whelpdale fired just over, with Tueday's winner Jon Meades also denied by the keeper.
Tom Beere lined up for an effort deflected wide. Scorer Elliott was denied and then struck a a post.
Somehow it stayed 1-0 at half time.
In the second half the speedy Elliott outrun the Peterborough defence, lobbed the keeper to hit the frame a second time.
But even given the profligacy on chances, Dons are eight games unbeaten and come away with a third successive away win.
They hold the last play-off place, while MK Dons slumped to 19th after a 3-0 home defeat to Southend.
