Butland moved to Palace in October from Stoke City.
Reflecting on the game as a whole, he told Palace TV: "I think second-half we improved. I think for what we did do, it didn't feel like we created much, which was a shame, but we were up against a good side and I just don't think we found that spark.
"[We are] frustrated and, for me on a debut I've been looking forward to for a long time and hoping for a positive result, it's bittersweet; nice to make my debut but also very frustrating to be out of the cup."
Butland then drilled into his own performance in greater detail, saying: "I'm in a really good place, looking for a change and a new start and I feel that, with the group we've got here, I've really felt that I'm back to my best [and] capable of showing my best.
"I was always looking forward to the opportunity to showcase myself a bit and hopefully I've done that tonight. It's a difficult game, a game of few chances, and I was a little bit disappointed with the goal – I was unsighted.
"I'll look at it – I'm my biggest critic and I'll always strive for the best. But I'm pleased with my overall performance and just disappointed we're out."