Peterborough keeper Joe Lewis saved a late penalty as Posh beat Plymouth.
Skipper Carl Fletcher put the visitors ahead when he poked in a Simon Walton free-kick.
Ryan Bennett pulled Posh level when he headed in Grant McCann's cross, before a Mark Little cut-back allowed Craig Mackail-Smith to slot in the equaliser.
When Bennett fouled Stephane Zubar in the box late on, Lewis was on hand to save Luke Summerfield's spot-kick and ensure Posh sealed the win.
Peterborough United manager Darren Ferguson told BBC Radio Cambridgeshire:
"All we can do get as many points as we can between now and the end of the season.
"Nerves will play a part, but my team have shown they can handle it. Most teams would have lost after a first-half performance like that.
"We've got the right character, but we know every game we've got remaining will be hard."
Plymouth Argyle boss Peter Reid told BBC Radio Devon:
"I though we were the better side and played the better football, but that's football and the way it goes.
"I am delighted with the boys, just disappointed we didn't take anything from the game."