Arsenal boss Arsene Wenger was left disappointed after Chelsea equalised through a corner and a free kick in the sides' draw at Highbury.
He said: "We suffered from set pieces, but we had some young players out there and we were too small as a unit.
"The way we conceded the two goals is regrettable, because we could have done better on both occasions.
"It is frustrating because we were twice in the lead but we were pulled back. We had chances to win the game."
Wenger, though, was pleased with the overall performance of his inexperienced side.
And he pointed to the superb partnership between Matthieu Flamini and teenager Cesc Fabregas in midfield as reason for optimism.
He said: "In the middle of the park, our oldest player was 20 years old. I would like to congratulate the players for showing fantastic qualities.
"This team has shown fantastic spirit and has a great future. It was an intense game, and we had much less experience than Chelsea.
"But I thought we did really well, and it was important for us to come back to the level we want to be at."