We bowed out on penalties having led 1-0 with only five minutes left of the tense quarter-final against Middlesbrough on Wednesday night.
Acting boss David brought in Rohan Ricketts for Gus Poyet from Saturday's defeat at Newcastle and he lined-up alongside Ledley King, Paul Konchesky and the more experienced Darren Anderton against Middlesbrough.
David reflected: "We started with a very young midfield, three youngsters in Konchesky, Ricketts and King. Anderton was the experienced one. They showed plenty of energy and that was pleasing.
"I have to take the positives out of the football part of the game, I can't do anything about penalties - they are in the lap of the gods.
"What really pleased me as well, especially after having to make the substitutions, was how we started to play good football again in extra time. Our fitness was also good.
"But the game has gone, it's history. We've got to live with these things and it will be a test of character, personality, morale. You have to come out fighting when you are down.
"Everyone has disappointments. It's a bad one when you are approaching a semi-final although it's even worse in a semi-final. That's football."
David Pleat highlighted the performances of our young midfield trio as he looked at the positives from our Carling Cup exit.