Larnaca managed to hold Palace at Selhurst Park in Thursday's first-leg of their round of 16 tie.
“Yeah, the feeling is definitely disappointment,” Johnson told TNT Sports. “It wasn't a game with loads of chances, but we thought we had a couple that we were unlucky not to score, and it would have been nice to get the lead; then, you don't know where the game goes.
“But overall it’s disappointment. It's tough to look back at the game straight after and see what the problem was with creating.
“At the end of the day it's 0-0, we can't have our heads too low, because next week we've got a big game – and one that we'll be ready for.
“To be honest, we're in the exact same position as we were going into this game. Even though it's two legs, I feel like we'll look back and see what we can do better this game.
“But at the end of the day, we're going into the next leg at 0-0, all to play for. We're confident, we know what we can do and we know what we have to execute better.”