Boss Jim Magilton felt that Peterborough's second goal marked a turning point in the Carling Cup first round tie. However, the Town manager was pleased with the performances of his young players.
Magilton said: "First of all I must congratulate Peterborough for a battling performance, but I can't help looking back to the point when we gave them a silly lifeline in extra-time.
"We were in control at that point and giving Guy Branston a free header ultimately proved costly.
"But I cannot fault any of the lads and the displays of several youngsters were particularly pleasing. However, results don't lie and we will keep the spirits high as we hope to turn things around."
Magilton has confirmed that Fulham midfielder Sylvain Legwinski is on trial with the Blues at present.
Peterborough manager Keith Alexander was pleased with his side, particularly keeper Mark Tyler: "We produced a great fighting performance and beating a Championship side is a feather in our cap.
"Tyler was absolutely outstanding and made several remarkable saves, but all the lads played their part. I had nine players volunteering to take penalties and all our spotkicks were first class."