The Posh Under 18s were beaten 4-2 by Colchester United on Saturday morning with striker Bolu Shofowoke continuing his fine start to the season with another goal.
The Peterborough United youngsters were undone by a direct U's side with Jimmy Unwin's side creating a host of chances in front of goal, but a combination of excellent goalkeeping and poor finishing ultimately proved costly as mistakes at the back allowed the hosts to run out 4-2 winners.
Benji McWilliams-Marcano, who was described as the 'best player on the pitch' by Unwin, scored a fine solo effort while Shofowoke raced onto a clever pass to nip in front of the goalkeeper to score.
Unfortunately for Posh, the U's exploited mistakes at the back and despite a 25 minute period in the second half, where the city youngsters were camped in their opponents half, the day ended in defeat.
"It was frustrating and it is definitely an area that we need to work hard on because we gifted goals and at any level of football, you will always get punished if you are defending poorly.
"We gave away a penalty, were punished for not clearing our lines as we tried to play through the press and individually we made mistakes. It is not a good recipe for success.
"We looked good going forward, created a lot of opportunities and on another day, we could have scored more, we had one cleared off the line and their goalkeeper made some good saves," Unwin said.
Posh host Swansea City in Professional Development League action on Saturday morning (11am).
Posh: Westcott, Sudakaran, Joseph, Christoudias, Aikins, Arber, McWilliams-Marcano, Mlityalwa, Shofowoke, Crozier, Simmons. Subs: Fitzpatrick, Bucknor, Norville, Miljkovic, Mfuri.