Matt Done fired home the only goal of the game as Sheffield United picked up a fourth win on the bounce against Peterborough.
United made a blistering start and Done had already tested Peterborough goalkeeper Luke McGee before putting the Blades in front on 13 minutes.
Goalmouth action came at a premium for the rest of the first half before Stefan Scougall forced McGee into a good save on 53 minutes.
Peterborough pressured for an equaliser in the second half and former Tottenham Hotspurs midfielder John Bostock fired wide from 25 yards.
But the Blades held on to rise into the League One play-off places in sixth.
Blades boss Chris Wilder said: “I thought it was a steady performance against real difficult opposition.
“They have hurt teams in this division in the past and it was a difficult shape to play against.
“We got off to a great start and got our noses in front. I thought for the first 25 minutes we were really good, without putting the game to bed.
“Their goalkeeper made two or three outstanding saves in that period. They got a foot-hold in the game, but they didn’t really create much in the six-yard box.”