Posh beaten 3-1 by Port Vale at the Weston Homes Stadium in latest Sky Bet League One fixture.
Peterborough United slumped to a 3-1 home defeat by struggling Port Vale to miss out on the opportunity to extend the advantage from the drop zone in Sky Bet League One.
While two of the goals scored by Vale were excellent free-kicks from Ethon Archer, the first and ultimately important goal was entirely preventable.
Posh did get back into the contest through James Dornelly and enjoyed spells of possession, but goalkeeper Joe Gauci was largely untroubled in the Vale goal.
It was Rhys CROASDALE who opened the scoring, calmly finding the bottom corner as Posh failed to engage in a defensive action following a long clearance.
Vale continued to cause problems and doubled their lead through ARCHER who floated a wonderful free-kick into the top corner after Peter Kioso had been penalised for a foul.
DORNELLY halved the deficit as he swept home a Matt Garbett set-piece, which lifted Posh in terms of the intensity, but Vale still caused problems on the counter-attack with Sherif a powerful presence.
Archie Collins sent a side-footed effort straight at Gauci on 48 minutes after a good lay-off from Leonard with the Posh number four also firing wide of the target.
On 57 minutes, ARCHER made it 3-1, another sumptuous free-kick from 25 yards after Dornelly this time gave away a free-kick.
Sherif should have made it 4-1 after a poor defensive pass from Kioso before Aderoju headed over following a corner kick. Posh return to action on Sunday against Burton Albion at the Weston Homes Stadium (1pm).
Posh: Bass, Collins, Khela (sub Sykut 82min), Lees, Lisbie, Mills, Leonard, Garbett (sub Aderoju 63min), Kioso (sub Kamara 63min), Dornelly, Shofowoke (sub Hayes 54min). Unused subs: Smith, Frith, Okagbue.
Port Vale: Gauci, Headley (sub Humphreys 70min), Hall, Archer, Croasdale, Sherif (sub Browne 81min), Shipley, Campbell, Ward (sub Waine 81min), Magloire, Hernandez (sub Gordon 50min). Unused subs: Amos, Shorrock, Bussell.
Half-time: Peterborough United 1-2 Port Vale
Full-time: Peterborough United 1-3 Port Vale
Attendance: 6,533 (219 Port Vale fans)
Referee: Harry Wager