Sheffield Wednesday suffered a 4-1 home defeat at the hands of in-form Peterborough, who posted their seventh win in eight games to cement their place in the top six.
First half goals from Craig Mackail-Smith, Lee Tomlin and George Boyd set the tone before Paul Heffernan pulled one back after the break.
But Boyd went on to make it four and despite a much-improved second half performance, Wednesday emerged pointless.
Posh threatened first through Mackail-Smith, who pulled the trigger on a fierce volley inside the box but Michael Morrison bravely thwarted the division's leading marksman.
The Owls were then dealt an early blow when Mark Beevers was forced out of the action following a clash of heads with Charlie Lee but Gary Megson's men pushed on and started to show encouraging signs.
But free-scoring Peterborough were always going to look dangerous on the break, as was evidenced 20 minutes in when Lee glanced Grant McCann's cross narrowly wide.
Wednesday forced Joe Lewis into action moments later when Gary Teale's looping cross almost had the keeper in trouble right underneath his crossbar.
But it was Peterborough who made the breakthrough on 25 minutes and it was that man Mackail-Smith who opened the scoring, latching on to a long ball over the top to confidently flick past Nicky Weaver.
The hosts needed a positive response and Michael Morrison headed Teale's free kick past the post but just as the Owls were getting a foothold on the game, Posh doubled their lead.
The warning signs were there of Peterborough's ability on the counter and so it proved on 34 minutes when they swiftly broke from an Owls corner and the ball founds it way to Tomlin, who executed a clever angled chip over the advancing Weaver.
Six minutes later it was three, with Boyd stroking home from the edge of the area after good work down the right from the effervescent Mackail-Smith and Wednesday went down the half time tunnel with a huge mountain to climb.
Heffernan came on for the second half but it was skipper Tommy Miller that came close to reducing the arrears minutes after the resumption, driving a crisp half volley that Lewis saved with his feet.
And on 51 minutes, the Owls did claw one back when Madine did well down the left to send a clever feed into the path of Heffernan, who smashed into the Kop net from close range.
Both sides then had goals disallowed for offside - Heffernan for the Owls before Ryan Bennett suffered the same fate at the other end.
But Wednesday had the edge, forcing Posh on the back foot, and Teale came within a whisker of getting something on Daniel Jones' cross from the left.
The Owls continued to press and looked far the more likely but Peterborough had the final word, with Boyd bagging his second on 81 minutes after Weaver allowed the forward's shot to squirm through his hands and roll agonisingly over the line.
Owls: Weaver, Hinds (Potter 75), Beevers (Jones 10), M Morrison, Reynolds, Teale, Miller, Coke, Osbourne, J Johnson (Heffernan 46), Madine
Unused substitutes: O'Donnell, O'Connor, C Morrison, Mellor
Peterborough: Lewis, Little, Kennedy, Zakuani, Lee (Basey 87), Boyd, McCann, Mackail-Smith, Rowe (Wesolowski 87) Bennett, Tomlin (Ball 74)
Unused substitutes: Langmead, Mendez-Laing, Davis, Jones