Gerardo Martino said Barcelona found it difficult to execute their style of play near Atletico Madrid's goal in their Champions League defeat on Wednesday.
Martino's side lost 1-0 with Koke's fifth-minute goal proving the difference, and the Blaugrana crashed out of Europe 2-1 on aggregate.
With the benefit of the early goal, Atletico had the luxury to pack in defensively, preventing Barcelona's famed tiki-taka passing at the edge of their box.
"Results happen for a reason," Martino said. "When Atletico were the better side, they scored their goal. We also had opportunities and just one goal from us would have changed the course of the game.
"At certain points, we couldn't do the things we wanted because of how our opponents played. Atletico kept a lot of players near their penalty area -- they did that very well and that made it hard for us to find any space.
The Calderon was rocking after Koke's goal, and the Argentine manager compared the atmosphere to what he experience in his native country.
"This environment is difficult to find in Europe, but it's more common in Argentina," Martino said.
"We have to keep fighting in the two competitions that remain for us now: the league and the Copa del Rey.
Midfielder Xavi Hernandez rued Barcelona's missed chances and was less willing to concede defeat.
"I don't know if they deserved to win. We'll see when we watch the game back," Xavi told Canal+.
"We had four or five clear chances and they have taken their only in the first 15 minutes. We deserved at least extra-time."