Mikael Silvestre has demanded that Arsenal's youngsters learn from the mistakes they made against Burnley on Tuesday night.
The Gunners exited the competition at the quarter-final stage as they suffered a 2-0 loss to the Championship side at Turf Moor.
Silvestre captained a youthful team and admitted they paid the price for their errors.
The 31-year-old Frenchman said in the Evening Standard: "You have got to learn.
"They should have won and a lack of concentration has cost us two goals. We had chances and it's a shame.
"It was an opportunity for them to express themselves (in the cup run).
"They did but we lost this game and you can see that it will hurt for a while.
"If we are not stupid, then we won't do the same again."