Sheffield Wednesday eased themselves away from the relegation zone with their first home win since August.
The Owls, who registered a first win in 10 npower Championship games at Ipswich last week, backed it up with a vital and deserved success over struggling Posh.
It was far from a classic at Hillsborough, but in-form Ross Barkley enhanced his growing reputation further when he struck less than 20 seconds into the second period with a deflected effort.
Defender Miguel Llera doubled that lead in the 76th minute with a header as the Owls looked on course for a routine win.
Peterborough, who had won their last two league games, made a game of it when George Boyd drove home from 18 yards, but Wednesday held firm.
The win sees Dave Jones' men leapfrog Posh in the table and Wednesday fans will hope that after their horror run of form through the autumn, they can finally start looking up.
That dire sequence of nine league games without a win finally ended with a superb 3-0 win at struggling Ipswich last week and the Owls were keen to maintain that momentum in the opening exchanges.
Indeed, they looked the more threatening and Barkley, scorer of a brace at Portman Road, tested Posh keeper Bobby Olejnik, who turned the on-loan Everton man's effort from distance around the post.
It was far from one-way traffic, but the Owls continued to carve out the chances and Llera headed a Jay Bothroyd corner narrowly over the bar.
Owls midfielder Paul Corry, who had been making Wednesday tick in recent weeks, suffered an injury and had to be replaced by fit-again Rhys McCabe and that disrupted the hosts' flow.
With Peterborough unable to take advantage the game descended into a low-quality affair played mainly in the middle third, with the half-time whistle coming as a relief to all.
However, the game needed less than 20 seconds after the restart to come to life and it was Wednesday that forged into the lead.
Virtually straight from kick-off the ball was pumped up to Chris O'Grady, he flicked on and Barkley fired home from inside the penalty with an effort that appeared to be deflected.
Unfortunately, that proved to be an isolated moment of excitement and the game reverted to the drab encounter of the first half.
The Posh have not been known for their inability to get on the scoresheet in recent years, but Chris Kirkland in the Wednesday net hardly had a save to make and it was Wednesday that looked like doubling their advantage.
There were shouts for a penalty when Michail Antonio was bundled over, but referee Darren Drysdale kept his whistle away from his lips and then the Owls winger prodded wide when he found himself in space.
Wednesday thought they had made the game safe with 14 minutes to go when Llera headed home Antonio's cross from six yards out for his third goal of the campaign to double their lead.
But Posh finally stirred and immediately gave themselves a lifeline when Body drilled in from the edge of the area following a corner.
However, Darren Ferguson's men were unable to launch a late onslaught and Wednesday saw it out relatively trouble-free.