A goal in each half from Peterborough's Conor Washington led to a seventh straight league defeat for the Spireites, the worst run since their relegation season back in 1988.
Add to that, no goals scored in the last five of those defeats and it confirms the size of the job Danny Wilson has to do at the Proact Stadium.
Washington struck in stoppage time at the end of the first half, bundling in from close range after Marcus Maddison was given too much freedom on the left of the box to cross in.
The defence looked for a flag, none came along, though Chesterfield did escape a goal from Jon Taylor after 71 minutes when he tapped in from a yard, but that warning was not heeded and within seconds, having given the ball away, Washington received in a mass Posh attack to fire beyond Tommy Lee, who managed to get a hand to the ball but he couldn’t keep it out.
From United’s opener, the hosts always looked likely winners with Chesterfield giving the ball away far too often and opportunities from crosses and free-kicks not being converted into chances in front of 7,153 fans.
Another tough task on Monday when Coventry come to Chesterfield who desperately need to start accumulating both goals and points.
With Wilson watching from the stands, Smith directed pitch-side operations at a Peterborough side that has now won eight of their last 11 games under new manager Graham Westley. Something like that from Wilson would go down extremely well in North Derbyshire!
Team news saw18-year-old youth teamer Derek Daly, normally a winger, make his debut at left back in a side with two changes. Dan Gardner also came in for Gboly Ariyibi.
Tommy Lee madehis 298th league appearance for the club to overtake Derek Niven and move into 17th spot on the all-time club list.
Peterborough: Alnwick, Smith, Taylor, Bostwick, Oztumer (Samuelson 69), Maddison, Santos, Washington, Beautyman (Baldwin 80), Coulibaly (Angol 69), Forrester. Subs: Henry, Fox, Addison, Nicholson.
Chesterfield: Lee, O’Neil, Evatt, Raglan (Wood HT), Daly (Novak HT), Hird, Gardner (Simons 66), Banks, Donohue, O’Shea, Ebanks-Blake. Subs: Cairns, Dieseruvwe, Ariyibi, Herd.
Ref: Andy Woolmer (Northants)
Booked: Banks (Chesterfield), Maddison (Peterborough)