There is one aspect of Spanish football that is rarely publicised - pernicious and vile, it seldom gets covered in the mainstream media.
As I walked to the Catalan derby on Saturday night, a police helicopter hovered ominously above in the cold winter night air, its light illuminating potential trouble.
It concentrated on a convoy of police riot vans which filled a street by a strip of rough neighbourhood bars.
Dozens of police, their faces obscured to avoid identification, stood in a line watching the Espanyol ultras.
As they were about to play hated rivals Barcelona, the ultras were more numerous, more animated than usual, shouting insults and making threatening gestures. It was only a minority, but a long standing vocal one.
Inside the ground, Espanyol fans screamed racist remarks without challenge whenever Eric Abidal or Daniel Alves, two of the Barcelona defenders, touched the ball.
The Frenchman and Brazilian ignored the bile and contributed to their team winning 5-1 against a side who had won all seven of their home league games. But they won't forget.
The racist chanters were a minority, but a high-profile one which continues to stain the decent reputation of the vast majority of Espanyol fans.
Those supporters had given rousing applause when Andres Iniesta's name was announced before the game … before booing every other Barcelona player with the hilarity and intensity you would expect between two big city rivals.
They did not forget Iniesta's gesture to Dani Jarque, their former captain, in the World Cup final, when he celebrated his famous goal by unveiled the words "Dani Jarque, you are always with us" nor that he had donated his shirt to be part of the tributes to his former teammate.
There was an even louder farewell for Iniesta after the game, with Espanyol singing "Iniesta! Iniesta!" and waving flags and placards in his honour.
The Barca midfielder was humbled and emotional. Those magnanimous fans far outnumbered the lunatic fringe in the 40,000 crowd.
And, thankfully, both Espanyol and Barcelona boast bigger and better organised fan groups than the extremists.
These renounce violence and create a great atmosphere for their players, as great fans should.
The Espanyol fans set the scene perfectly on Saturday and were far louder than their Barca equivalents are at Camp Nou.
They raised a huge banner reminding the world that there is more to Catalunya than Barcelona. They held up 40,000 blue and white cards to cover both tiers of the new stadium in their colours.
And they roared loud and proud … until Pedro scored after 18 minutes. The goal - and a second one 11 minutes later from Xavi - stunned the young home side into submission and the game was over with two thirds of it left to play.
Barca were more experienced, committed and technically and tactically superior.
Espanyol did become the first team to beat Victor Valdes in six matches, but Osvaldo's goal was a mere consolation.
They had been easily outclassed, without shame for Barca are currently a level above any side in world football and continue to create freakish statistics.
They have scored 31 goals, conceding just one in the last five games. They have won all 10 away games this season - a club record - and have scored five or more goals against seven teams this season.
Barca take on Athletic Bilbao in the the Copa Del Rey tonight at Camp Nou. Pity the poor Basques. Most Espanyol fans did not like what they saw at the weekend, but they acknowledge the strength of their enemy.
A top-six finish will be an achievement for them, as will banishing their lunatic fringe.