The Posh under 18s were beaten by Birmingham City in Professional Development League action on Thursday.
The Peterborough United under 18s were beaten 5-1 by Birmingham City on Thursday afternoon in a game that was played in very wet conditions.
The game was goalless at the half hour mark, but the Blues then took control, scoring three times before the interval with striker Tyler Winters netting in the 44th minute.
The Blues added two more goals in the second half as Posh lost Fabian Claxton to injury. Lead Coach Jimmy Unwin said: "The first half performance was quite positive particularly in the first 30 minutes, but obviously conceding three goals just before the interval gave us a bit of a mountain to climb.
"The second half display was not as good as the first in terms of the way we played and it ended in a disappointing scoreline."
Posh: West, Toynton, Claxton, Rose, Holley, Marcon, Gilbert, Odei-Larbi, Kelmendi, Beech, Winters. Subs: Sakalas, Davies, Chagunda, Freeman.