Barcelona boss Xavi was shocked at chant aimed at Barcelona by Athletic Bilbao fans

Barcelona manager Xavi said he was saddened by the hostile reception his side received during an away win against Athletic Bilbao on Sunday.

Brazilian winger Raphinha earned Barcelona a hard-fought 1-0 win with a fine strike just before half-time, a result that maintains their nine-point lead at the top of La Liga.

However, given events off the field over the weekend, the result at San Mames was never going to be the main talking point.

On Friday, prosecutors filed corruption charges against Barcelona relating to payments made to a company owned by the former vice president of the refereeing committee.

The prosecution alleges that Barcelona bought favourable treatment from referees between 2001 and 2018.

Barcelona paid a total of €7 million to a company owned by Jose Maria Enriquez Negreira during that period and claim the payments were for "technical reports on refereeing."

During Sunday night's match in Bilbao, the home fans threw bank notes with Barca's badge and "mafia $" written on them and chanted for Barcelona to be "relegated to the second division."

After the match, Xavi admitted he was surprised by the hostility directed at his team.

"I respect the fans at San Mames," he said during his post-match press conference.

"They have always treated me well, but I was surprised at the hostile atmosphere towards Barca.

"It was sad to see. [Barca] are being judged before time, which I don't think is good for society. Everyone is free to [air their opinion], and I respect all opinions, whether I agree with them or not, but it made me sad."

Xavi also insisted that outside noise will not impact his team's performances on the pitch.

"We have not spoken about it in the dressing room with the players," he said.

"We are here to win and are focused on the football. We are all professionals."

Joining Barcelona on the list of defendants are former Barca presidents Sandro Rosell and Josep Maria Bartomeu, along with Enriquez Negreira.

On Sunday, Real Madrid confirmed that they will join the complaint filed against Barcelona. La Liga and the Spanish FA are expected to do the same.

In response, Barca president Joan Laporta published a defiant statement on Twitter.

"Barça is innocent of the accusations made against it and is the victim of a campaign, that now involves everyone, to harm its honourability," he said.

"It is no surprise, and we will defend Barça and prove that the Club is innocent. Many will be forced to rectify."

Barcelona and Real Madrid will go head-to-head at Camp Nou on Sunday evening.