Burnley won the game 2-0 after a brace by Kevin McDonald.
“We had six one-on-ones with the keeper and we didn’t score,” Wenger told Sky Sports.
“We were a bit fragile at the back as well, but overall we had plenty of chances.
“When you do that against teams in the quarter-final of the cup, if you have six one-on-ones with the keeper and do not score, you have to question the qualification and that is what happened tonight.
“You praise the goalkeeper and question the strikers.”
He added: “We had the potential to go through and we lost tonight against the least difficult team of the three we played.
“That is what young players learn. In football it is efficiency and focus from the first minute on and when you don’t have the right focus you pay for it.
“They have a lot to learn many of them. The potential is there, and even tonight away from home they didn’t hide, they tried to play and we had plenty of chances.”
