Academy Director Tony Carr admitted that three uncharacteristic defensive errors had cost West Ham United dear in a 3-1 Barclays U18 Premier League defeat at Bolton Wanderers.
The Hammers travelled to Lancashire for their third league match of the 2012/13 season unbeaten after a 2-2 draw at Reading and 2-1 home win over Everton.
However, Carr conceded that the U18s just did not produce the goods against Jimmy Phillips' side on Saturday, Kieran Sadlier's second-half consolation goal aside.
"We started the game quite brightly considering we had travelled a long distance and they came out of the blocks quickly. We started very well but then, uncharacteristically, Frazer Shaw made a mistake trying to dribble out of defence and he got dispossessed.
"At that point we were all out of shape and they got in a shot that hit the post and put the rebound in, so after a bright start we found ourselves one down after ten minutes.
"They tried to pin us inside our own half and pressed very high and we just couldn't live with that. We tried to play short when we perhaps should have tried to turn them around and get up the pitch and get the game in their half a bit more.
"We slowly got into the game without threatening, save for a couple of half-chances. In the second half we tried to change the game by getting the ball in their half a bit more, but then we made another mistake.
"Manny Onnariase is a 15-year-old schoolboy and is learning but he dribbled out of defence and tried to make a pass that was intercepted and they went down the left and a shot came in that Sam Baxter parried and they put the rebound in again. Two basic errors put us 2-0 down.
"We got one back through a good move down the right. Nana Boakye-Yiadom, who had come on as a substitute, put in a good cross and their goalkeeper parried it. We intercepted the loose ball and Kieran Sadlier put it in. With 20 minutes to go, I thought we might get something out of the game.
"They started to go on the back foot and looked to be tiring, while we were finishing strongly, but then we made another uncharacteristic mistake.
"Josh Siafa, who was playing at right-back, got the ball just outside our box and tried to pass it square. The ball was intercepted and bang, we're 3-1 down and the game was over at that point, really.
"Overall, it was disappointing but the positives are that we're a young side with a young defence that is still learning the game.
"Boys are being pushed up to the Development Squad, who have made a great start to the season, and not every team can win every game so we have to move on to the next one."
West Ham United U18s: Baxter, Siafa (Homans 77), Onnariase, Nasha, Shaw, Cullen, Miles (Boakye-Yiadom 64), T.Tombides (Mavila 79), Sadlier, Bywater, E.Lee