Darlington bounced back from a goal down to avoid equalling a club record ninth successive defeat with victory against big-spending Peterborough.
The visitors took the lead in the 23rd minute when Adam Smith coolly side-footed past home keeper Lee Jones.
But David Wheater headed in a Clark Keltie free-kick to level and then Julian Joachim's header from Neil Wainwright's cross put Darlo ahead.
Joachim raced clear on the hour to seal the Quakers' first win since November.
Darlington: Jones, Close, Tim Ryan, Wheater, Horwood, Wainwright, Keltie, Rowson, Johnson (James 78), Joachim, Armstrong (Ngoma 90).
Subs Not Used: Stockdale, Holloway, Reay.
Goals: Wheater 41, Joachim 51, 61.
Peterborough: Tyler, Newton, Branston (Futcher 52), Morgan, Arber, Low, Butcher (Gain 71), Hyde, Smith (Benjamin 64), Boyd, Mclean.
Subs Not Used: Jalal, Yeo.
Goals: Smith 23.
Ref: R Shoebridge (Derbyshire).