Simon Clark was left to rue a missing clinical edge in front of goal as Notts' under-18 side were put out of the FA Youth Cup at the first-round stage by Chesterfield.
Three first half goals were enough to give the Spireites victory and, although Alex Howes pulled a goal back late on, it was not enough for the young Magpies.
And Clark was disappointed with his side's showing in the opposition's penalty area.
"For all of the play and possession we have had and the chances we created, our conviction in the final third was not there tonight," he said.
"We have had good build-up and got into good areas while dominating large amounts of the ball but we just didn't make the most of it.
"We've prepared really well by scoring nine and conceding one goal in our previous two games before tonight but we didn't have the ruthlessness when we got within shooting range to pull the trigger. You aren't going to be able to score perfect goals.
"We've conceded goals which are defendable, which is really disappointing, but there were some good individual performances.
"I've told them football is a tough career. For the second-year scholars, it was their last chance at the FA Youth Cup.
"But they need to come in tomorrow with their heads up high. They need to learn from it and take it out on Scunthorpe in our next league game."