Academy Director Tony Carr admitted he and his players had been left gutted after losing their unbeaten start to the FA Premier Academy League season.
West Ham United's Under-18s had won six and drawn two of their opening eight matches, only to see their dreams of compiling a defeat-free campaign scuppered by a 2-0 home defeat by Charlton Athletic.
Carr admitted his team had not done enough to warrant a win or a share of the spoils at Little Heath.
"We are all disappointed that our run has come to an end," he said. "On the day, Charlton were the better team and, although we did have our moments, we were just a little bit off the pace.
"Charlton were bigger and stronger than us and we didn't get going until we had fallen 2-0 down. In the first half, Elliot Lee and Matthias Fanimo (pictured) both missed good chances to score, then Blair Turgott had a really good opportunity in the second half, but we couldn't get the first goal we needed to give us some impetus.
"We have now got to pick ourselves up and start another unbeaten run."
Carr, who spent Saturday afternoon watching young Academy professional Dominic Vose in action on loan for Blue Square Bet Premier side Braintree Town, admitted the disappointment of losing had been compounded by the fact his side do not have a fixture next weekend.
"It was inevitable that we would lose at some stage because we were not going to go through the whole season undefeated, but it would have been nice to go into the break still unbeaten.
"Saying that, I have to give credit to Charlton because they took their chances and worked very hard to protect their lead."
The U18s return to action at Fulham on Saturday 29 October.
West Ham United U18s: Larkins, Young, Potts, Chambers, K.Lee, Hurley, Sadlier (Bywater), Miles (Powell), Turgott, Famino (Shaw), E.Lee