Barcelona head coach Ronald Koeman "respects" Gerard Pique's opinion and has backed the defender to do his talking on the pitch in Saturday's clash with Real Madrid.

La Vanguardia published an explosive interview with Pique on the eve of the first Clasico of the season in which the long-serving defender heavily criticised his club.

The 33-year-old hit out at president Josep Maria Bartomeu in particular over his handling of Lionel Messi's contract saga and admitted Barca have gone backwards since 2015.

Pique did reserve some praise for new boss Koeman, however, and the Dutchman insisted he has no problem with the timing of the interview.

"He has been here for many years and I have been here for three months," Koeman said at a pre-match news conference on Friday ahead of the Camp Nou meeting with Madrid.

"He has his opinion and I respect it. He's smart and knows that if he does an interview of this type, tomorrow he will be ready and play well. I respect all opinions if he is involved."

Pique has been named in a 23-man squad that also includes the returning Jordi Alba and misfiring forward Antoine Griezmann, whose role in the side has been questioned.

Griezmann has yet to score, assist or create a single chance for one of his team-mates in LaLiga this term from four starts, but Koeman is expected to stick with the Frenchman.

"Like anyone he is available to play," Koeman said. "It is not good to discuss his role ahead of every game. We have many more players and want everyone at their best level.

"The team is always the most important thing and we choose the best players for each match."

Griezmann's poor return is in stark contrast to Ansu Fati, the teenage attacker having scored four goals in five appearances this term - more than any other Barca player.

Fellow youngster Vinicius Junior has also been in good form, scoring in three of his last four appearances, and Koeman can see both players getting better over time.

"We know that they are two very good players despite their age," he said. 

"They are learning many things and their trajectory is going very fast. For me the age of the player is not important - what matters to me is their performance.

"Ansu Fati will be a star in the future, but he must work and develop. We will support him to be one of the best in the world, and we will do the same with the other youngsters."

Barca, who like Madrid suffered a surprise defeat in their last league outing, are seeking a first Clasico win in three attempts.

The Catalan giants have failed to score in the last two Clasicos and Koeman acknowledged the importance of picking up a positive result this weekend to rebuild confidence.

"It is important, of course," he said. "The players deserve it for the work they are doing every day. They show a lot of ambition and have started playing in another system. 

"They have shown ambition and hunger. A game against Madrid is always something a bit more. If you win a match, everything is easier."