Flying winger David Farrell ended Posh's home jinx with a silver-goal winner to finally sink Third Division Torquay in an LDV Vans Trophy cracker.
Farrell was left with the easy task of tapping in from close range after Torquay keeper Kevin Dearden had spilled a 97th minute Andy Clarke shot into his path.
Farrell’s effort handed Posh their first win of the season at London Road after drawing two and losing four of their previous six games on home soil.
Barry Fry's side looked to be in for a comfortable night when captain Sagi Burton fired them ahead with his first goal for the club. Burton coolly converted from the penalty spot after a shove by defender Craig Taylor Posh frontman Calum Willock. But Torquay hit back on the half-hour when Tony Bedeau sped down the right and crossed for Kevin Wills to hook home from an acute angle.
But Second Division Posh needed only 90 seconds to put themselves back on top when match-winner Farrell touched a deep cross down into the path of Clarke and the veteran 36-year-old striker did the rest.
Torquay hauled themselves level for a second time eight minutes before the break when young frontman Jimmy Benefield stooped to nod home from five yards following a half cleared corner.
Despite a glut of chances at both ends in the second half, the tie went in to extra time and that is when Farrell slotted home the decider.
Benefield wasted a decent chance to equalise yet again when he smashed a late effort over and with that miss went the Gulls hopes of staying in the competition.