Shaq Coulthirst's double ensured Peterborough saw off non-league minnows Chesham 2-1 in the FA Cup first round.
The team sitting eighth in League One were second-best for much of the first period against Southern League Premier Division opponents.
Posh eventually hit the front through a long-range thunderbolt from Coulthirst five minutes before the break.
Marcus Maddison, Michael Smith and substitute Gwion Edwards all squandered glorious opportunities in the second half before Coulthirst doubled the lead with 20 minutes to go, sliding in to meet a low Smith delivery from the right.
But Chesham, who sit 94 places below their hosts in the English football pecking order, refused to roll over.
They halved their arrears when Ryan Blake - who struck in their famous first-round win at Bristol Rovers last season - pounced on a weak Michael Bostwick back pass to score.
Chesham were not far away from earning a replay when Bruce Crilley put a late diving header over from a corner, but there was no fairytale fightback for Andy Leese's men.