The Northampton Town under 18s travelled to Leyton Orient on Saturday in their latest EFL Youth Alliance fixture.
The Cobblers were beaten 2-1 in the capital, bringing to an end a fantastic unbeaten run. Jack Newell's goal wasn't enough as Jon Brady's side suffered defeat for the first time since the end of February.
"We didn't adapt to the conditions as well as Leyton Orient," he said.
"It's been a fantastic run and I think it was 25 games unbeaten but maybe one or two of the players had half an eye on Wednesday. That is a big game for us but there are definitely lessons we can learn from this. It's important for players to just focus on one game at a time and you can't take your eye off the ball or you will get punished.
"Our performance levels dropped a little bit today and it's a reminder to all of the players that the standards we've set over the last few months need to be maintained."
Next up the under 18s take on Swindon Town in the second round of the FA Youth Cup at the PTS Academy Stadium on Wednesday (14 November), kick-off 7pm. Admission prices are £3 for adults and senior citizens and £1 for under 18s. The winner of the second round tie will face a trip to Arsenal in the third round.
"It was great to see so many people supporting the boys in the first round and hopefully there will be another big crowd in on Wednesday," said Brady.
"It was a great experience for the boys playing under the lights at the PTS and they are all very appreciative of the support they have received.
"Swindon will be tough opposition but we will be giving it everything to try and get ourselves into the third round."