Second-half goals from Ross Barkley and Miguel Llera secured back-to-back wins for Sheffield Wednesday and helped them clamber away from the Championship’s bottom three.
Wednesday had not won in the league at home since August 25, and their victory at Ipswich last Saturday was their first in the league since that day.
It was a run that dropped Dave Jones’s side into the relegation zone.
But without being at their best, Wednesday made it two wins out of two against fellow strugglers as Peterborough were beaten in front of 22,406 fans at Hillsborough.
After a poor first half in which neither side created much, Wednesday took the lead just 10 seconds into the second period.
Lewis Buxton’s ball forward was flicked on by Chris O’Grady and midfielder Barkley - who had run beyond the defence - met it with a first-time shot beat Robert Olejnik at his near-post via a slight deflection off of Grant McCann.
Wednesday looked to have sealed the win 14 minutes from time.
Following the initial breakdown of a move, Michael Antonio floated a ball back into the danger zone with a marvellous cross with the outside of the right boot and Miguel Llera met it with a powerful header into the roof of the net.
But three minutes later George Boyd’s shot from the edge of the area found its way through a ruck of players to give Peterborough hope and set up a nervous finale.
Jones said: “I thought it was a hard-fought victory. I don’t think we played as well as we have been but sometimes you’ve got to grind out results.
“I thought the first half was a bit slow and no tempo to it from either side. I don’t know whether Darren’s side had tried to force that upon us but we fell into a very low-tempo game and there wasn’t much happening.”
He added: “The day was dull, everything about it was dull and well done to the crowd because second-half they got us going a little bit because it was just such a low-tempo game.
“There was not a great deal happening but sometimes you get those games and you’ve got to make sure you come out on top and that’s what we did second half.
“We’ve probably played far better than that and come away with nothing so that’s how it goes sometimes.
“I was glad they put the lights on, it was just such a dull day.
“Everybody was getting into that ‘let’s all go home’ sort of mode.”