Aaron Mclean's volleyed effort earned Peterborough an FA Cup third-round replay against Plymouth after home boss Keith Alexander had been sent off.
Hasney Aljofree put the visitors ahead on 74 minutes with a re-taken penalty after Guy Branston fouled Reuben Reid.
Alexander was sent to the stands for protesting against the goal, but Mclean fired home from Mark Arber's lay-off to ease the manager's frustrations.
It was just reward for the hosts who matched Argyle in a well-fought match.
Peterborough manager Keith Alexander:
"The referee had a diabolical game - you never get a fair crack against bigger sides.
"It was a really shocking decision to order a retake of the penalty.
"He would not talk to me for 30 minutes and by that time the officials have had a chance to get their story straight."
Plymouth boss Ian Holloway on Aljofree celebrating in front of the Posh fans and being hit by two bottles:
"To celebrate like that was a disgrace and I would have thrown a bottle at him myself.
"The keeper made a great save and there was no need to disrespect their fans.
"A bit of common-sense was needed and only the captain Lilian Nalis showed any by getting the players back."
Peterborough: Tyler, Newton, Morgan, Futcher (Branston 10), Arber, Low, Butcher, Strachan (Benjamin 77), Day (Yeo 63), Mclean, Crow.
Subs Not Used: Stirling, Richards.
Goals: Mclean 78.
Plymouth: McCormick, Connolly, Sawyer, Seip, Aljofree, Norris, Nalis, Buzsaky (Dickson 90), Capaldi, Samba (Summerfield 61), Reid (Hodges 81).
Subs Not Used: Gosling, Mason.
Sent Off: Connolly (64).
Booked: Sawyer, Connolly, Capaldi, Seip.
Goals: Aljofree 74 pen.
Ref: C Boyeson (E Yorkshire).