Danny Cadamarteri admitted his side lacked the killer instinct to avoid an FA Youth Cup shock against Plymouth Argyle.
The Clarets dominated for long spells at Turf Moor and had plenty of sights of goal to make it into round five.
But a real clear-cut chance remained elusive and Burnley couldn’t beat goalkeeper Michael Cooper – set to be on the bench for the Pilgrims in League One against Bury on Saturday afternoon.
And Argyle then grabbed an injury-time winner with their only effort on target from Billy Craske to follow up their penalty shoot-out win over Manchester City in the last round.
“It’s really frustrating. I’m gutted for the boys,” said Burnley youth boss Cadamarteri.
“To be fair we had the lion’s share of the play, but Plymouth have come here to do a job and same as the previous round when they played Manchester City they did pretty much the same thing and camped in and we have been hit by a sucker-punch chasing the game at the end.
“We probably didn’t work the goalkeeper as much as we would have liked in the first half. But we did then work him and the goalkeeper had an outstanding game.
“Even though we controlled possession and controlled the game I don’t feel we did enough to go and create and score a goal.
“We’ve got to take it on the chin and due respect to them. They’ve travelled up a long way and they’ve done a job.”
The Clarets’ youngsters slumped to the ground after Plymouth’s late winner and Cadamarteri hopes the experience will ultimately stand them in good stead.
He added: “That should hopefully build resilience. I’ve told them all in the dressing room to embrace the disappointment and how they feel now.
“There was a nice crowd out for them to watch the game and if you want to play in front of big crowds in their football careers they’re going to face disappointments and that’s the learning curve for them.
“We’ve said to them to embrace that, reflect on that tonight, reflect on it tomorrow, put it to bed on Sunday and then we come in on Monday and we start to continue the second half of the league season and look to the Lancashire Cup as well.”