Cubarsi admits his transition to the senior team has been made easy thanks to the club's attitude towards their own homespun youngsters.
He said at his Champions League media conference: "I have shared changing rooms with players from La Masía and that makes coexistence easier. Barça is giving us support through La Masía.
"La Masía is a training school, they train us to be good footballers. They give us many opportunities and energy."
Asked by Lamine Yamal, with which he shares a generation, Cubarsí was clear about everything that being in the first team now means.
"Both Lamine and I, if they ever told us that we were here two years ago ... no-one would believe it. We have to thank the club and the staff who have given us the opportunity to debut, to demonstrate that we can play."