A first half penalty from Jamie Reid earned Stevenage all three points at the Weston Homes Stadium.
Peterborough United suffered their first defeat under Luke Williams as visitors Stevenage moved to the top of the Sky Bet League One table following a narrow 1-0 victory at the Weston Homes Stadium.
It was a tale of two spot-kicks, one that was given and one that was not. Tom O'Connor was penalised for a handball at the back post, but then the officials failed to spot a blatant handball in the box as Posh kept a move alive.
In terms of clear-cut chances, the game was devoid of them. Alex Bass didn't have much to do throughout the 90 minutes, while counterpart Filip Marschall was busier without being fully extended.
REID opened the scoring on 20 minutes, calmly sending goalkeeper Bass the wrong way from the spot. Harley Mills fired wide of the near post after a decent foray into the box on 50 minutes before the left-back fired a free-kick into the wall.
A minute later, Posh had those strong appeals for handball turned down by the officials with O'Connor cautioned for his protests. O'Connor headed a corner kick over the top before Marschall went down with a mystery injury that was soon rectified following a chat between the Stevenage management and players.
Substitute Matt Garbett was kept out smartly by the keeper on 76 minutes with Ben Woods also seeing a deflected effort gathered by the shot-stopper. There were seven minutes to try and find a leveller, but the visitors managed that time expertly to secure a 1-0 win.
Posh: Bass, Collins (sub Lindgren 75min), Odoh (sub Khela 62min) , Lees, Woods, Lisbie (sub Frith 75min), Mills, Morgan, Leonard (sub Garbett 62min) , O’Connor, Kioso. Unused subs: Reyes, Johnston, O’Brien-Brady,
Stevenage: Marschall, James-Wildin, Butler, Sweeney, Phillips, Ahadme (Sub Thompson 73min), Kemp (sub Pattenden 84min), Goode, Freestone, White (sub Lubala 73min), Reid (sub Campbell 84min). Unused subs: Ashby-Hammond, Malcolm, Patterson.
Half-time: Peterborough United 0-1 Stevenage
Full-time: Peterborough United 0-1 Stevenage
Attendance: 6,840 (511 Stevenage fans)
Referee: Ed Duckworth