Roy Keane said his Town side paid the price for not taking their chances as Blues bowed out of the Carling Cup at Peterborough.
Tamas Priskin put Town ahead on 15 minutes with his first goal for the Club but saw a penalty saved by Joe Lewis and it was Posh who progressed to the next round through goals from Lee Frecklington and George Boyd.
"We had a very good start and then had the penalty to make it two but we didn't take that chance and that is proving to be typical of our season at the moment, not taking the vital moments," said the Town boss.
"We seem to continue to make winning a football match difficult for ourselves. We had opportunities in the second-half when we could have put the ball in the net but didn't take them.
"Their second goal was very disappointing from our point of view and it's hard to take for the players, the supporters and everyone involved with the Club because we obviously wanted to win the game. "
Pablo Counago had a hand in Town's opener in his first game of the season after being sidelined with a groin injury and Roy added: "We didn't want to risk him for too long because it's his first game back but his awareness and hold up play gave us a boost."