For long periods, Posh can be pleased with their overall performance, but two soft goals ultimately earned Sheffield Wednesday all three points.
Peterborough United suffered a 2-1 defeat to promotion favourites Sheffield Wednesday at the Weston Homes Stadium and manager Luke Williams will be disappointed in the manner of the two goals conceded with the Owls taking advantage of defensive lapses to secure all three points.
After a competitive 35 minutes, a poor pass out of defence put pressure on a team-mate and after an initial effort at goal looked like it was going to be cleared off the line, a clearance rebounded off Josh Feeney and bounced into the back of the net.
If that was a poor goal to concede, the winner was another frustrating moment for the hosts as an in-swinging corner was bundled in at the near post by Yan Valery.
Posh played some good stuff between the boxes and again carved out opportunities in front of goal, but couldn't force a deserved equaliser despite the best attempts of Danny Ormerod and Harry Ashfield.
Leonard saw an early effort kept out by goalkeeper Joe Lumley after some good football involving Bolu Shofowoke and Ben Woods.
Posh lost the services of defender Tom O'Connor to injury on 12 minutes and replacement David Okagbue had a chance to score on 18 minutes, but headed wide.
Bass did well to keep out a Barry Bannan effort on 26 minutes before Leonard fired wide of the target after more good pressing from Woods and Williams.
On 37 minutes, the Owls opened the scoring and it will go down as a Feeney own goal, but he was probably a tad unlucky as he was in the wrong place at the wrong time as Okagbue attempted to clear off the line.
On 48 minutes, Posh levelled the scores as WOODS powered home a header from a delicious James Dornelly centre. Lowe fired over within 60 seconds at the back post before Lumley somehow kept out a deflected effort from close-range.
Jones saw a shot blocked before Bannan fired inches past the post with that trusted left-foot. Burstow fired wide at one end before substitute Danny Ormerod fired wide after doing well to cut inside onto his right-foot.
On 78 minutes, the visitors got themselves back in front as VALERY headed home at the near post following an in-swinging corner kick. Ashfield saw a deep cross tipped over by Lumley before he fired inches wide from the edge of the box.
Khela, Ormerod and Ashfield all tried to stab home from close-range in stoppage time after a goal-mouth scramble, but ultimately Posh couldn't force the equaliser they deserved.
Posh: Bass, Kelly (sub Ashfield 74min), O’Connor (sub Okagbue 12min), Jones (sub Khela 74min), Leonard, Williams (sub Ormerod 62min) , Feeney, Mills, Woods, Shofowoke, Dornelly. Unused subs: Smith, Weir, Conn-Clarke.
Sheffield Wednesday: Lumley, Cooper (sub Weaver 46min), Valery (sub Palmer 85min), Slattery, Lowe (sub Burstow 57min), Bannan, Heskey (sub Mitchell 57min), Morrison, Otegbayo, James, Keillor-Dunn (sub Al-Hamadi 57min). Unused subs: Trueman, Grainger.
Half-time: Peterborough United 0-1 Sheffield Wednesday
Full-time: Peterborough United 1-2 Sheffield Wednesday
Attendance: 10,848 (3,910 Sheffield Wednesday fans)
Referee: Andrew Humphries