Stand-in strikers Calum Willock and Richard Logan grabbed the goals to steer Peterborough United into the FA Cup second round at the expense of Hereford United, who were easily the better side up to the break.
With first-choice front men Leon McKenzie and Andy Clarke ruled out through injury, Posh boss Barry Fry had to rely on loanees Willock and Logan for the goals that shattered the Conference leaders' dreams in the space of six second-half minutes.
Fulham youngster Willock punished a 53rd minute mistake by Michael Rose to send a 20-yard rocket past Matt Baker and into the roof of the net and the Hereford goalkeeper was just as helpless when Adam Newton's inviting cross was put away at the far post by Logan, who had been frozen out at Third Division Boston.
Fry was delighted with the pair's showing, commenting: "We had everything to lose and were poor in the first half, but after getting the goals never looked in danger.
"I was especially pleased for Willock, who has hit the woodwork in the last two games and thought Logan took his chance equally well.
"The FA Cup is all about winning and going into the next round and I don't think anyone could say we didn't deserve to do that," Fry added.
The first half was a tale of two penalties that never were. Hereford even had the ball on the spot after Chris Kanu tripped Paul Parry, but referee Fraser Stretton changed his mind after consulting an assistant and Danny Williams made nothing of the free-kick from the edge of the box.
Posh then appealed as a man when Willock went tumbling as he powered towards goal, but this time referee Stretton simply waved play on.
Hereford stuck to their football even when trailing and manager Graham Turner's only complaint was over the penalty incident.
"He said: "It was a ludicrous decision that got our lads on a high at the chance of going ahead only for him to change his mind. "It is credit to them that they managed to keep their composure."