La Roja destroyed the World Cup finalists in the Nations League clash in Elche on Tuesday, breezing to a 6-0 triumph, the biggest defeat in their opponents' entire history.
Madrid superstars Dani Carvajal, Sergio Ramos, Nacho Fernandez, Dani Ceballos, Isco and Marco Asensio all started the match, while Sergio Busquets featured as the only Barcelona player in the first 11.
The selection raised some eyebrows given Luis Enrique's three years as Barca boss between 2014 and 2017, but the 48-year-old has no interest in which clubs his chosen players represent.
"I did not know or care," he told a news conference when asked about the number of Madrid players in his line-up. "They belong to the Spanish national team, nothing more. They're not from one team or another. I see only the shirt of the national team.
"It doesn't make sense to compare national teams and clubs. We have our idea of playing football and today, everything was amazing. We started with some doubts, but then we were brilliant, with incredible goals.
"What I liked most about these 10 days was the attitude of the players. From what I've seen, regardless of the result, I'm delighted."
Croatia missed early chances through Ivan Santini and Ivan Perisic, but Spain never relinquished control once Saul Niguez broke the deadlock 24 minutes in.
Asensio doubled the lead brilliantly and then forced an own goal from goalkeeper Lovre Kalinic with a stunning strike from distance, before the winger set up Rodrigo Moreno, Ramos and Isco in the second half.
The variety in Spain's attacking play pleased Luis Enrique more than anything else after their somewhat shaky opening to the heavyweight clash.
"We were facing Croatia, a team who press very well, and it was difficult for us to get the ball out. Everything changed as of the 20th minute," he said.
"We had fast, direct football, with good work between the lines. Ramos made the changes of direction, Asensio was tremendous with his goals and passes, we had the success and speed of Rodrigo, Busi distributing the ball... I've nothing to object about. I liked almost everything."