Sergio Busquets conceded Barcelona's pre-season defensive problems are a concern ahead of the Supercopa de Espana first leg at Sevilla.
Last season's double winners won three of their four friendlies without keeping a clean sheet and they were resoundingly beaten 4-0 by Liverpool at Wembley.
"We have to be more solid defensively," said Busquets ahead of the trip to the Ramon Sanchez Pizjuan to face a side Luis Enrique's men needed extra time to beat in the final of the Copa del Rey.
"In the pre-season it often happens that we have a lot of games with many goals in attack and defence.
"We do not have any advantage. Physically they have had many days to prepare this match. On a mental level, it is clearly easier to prepare a game when you win a title."
Barca were active in the transfer market during the close-season and Busquets is buoyed by the captures of Samuel Umtiti, Lucas Digne, Denis Suarez and Andre Gomes.
"Clearly, we have strengthened with more players than in other years," he said.
"We still have a lot to improve tactically with the new players. They are eager and very excited. With their individual quality they have some insurance and are just adapting."
Busquets was part of a stunning generation of talent to emerge from Barcelona's La Masia academy, but that production line has comparatively dried up during recent seasons, with new recruits such as those brought in over recent months preferred to youth-team graduates.
"It is clear that once it was normal to leave many [young] players in the squad," Busquets added.
"This is a topic of football that has changed. It was not normal what happened in those days.
"Something has to be done better to leave more players."