Pique riled the Periquitos by labelling them a small club in a thinly-veiled dig at full time, having helped his side overturn a one-goal first-leg deficit to prevail 2-1 in the semi-final tie.

Teammate Busquets made a similar comment after the match, referring to Espanyol as a team from Cornella - a small suburb of Barcelona - and criticised the opposition fans for over-celebrating following their slender triumph last week.

Espanyol want the matter looked into, as well as alleged xenophobic chants by Barca supporters at Camp Nou on Thursday night.

A club statement read: "In relation to the statements of Pique, just as Sant Adria del Besos hosts our Sports City Dani Jarque, Cornella de Llobregat and El Prat de Llobregat are the cities whose municipal terms host the RCDE Stadium.

"Both cities belong to the Metropolitan Area of Barcelona and stand out as two of the cities with the most population in Catalonia, mostly working and struggling families, with family roots throughout Spain and in other countries, which are and always will be an example of integration and progress and a pride for our land.

"We consider that any demonstration in a clearly derogatory tone towards these cities, such as those pronounced and reiterated by Mr Pique towards the city of Cornella. In relation to the statements of Busquets, it is inconceivable that an athlete declares that a rival can not celebrate a victory, achieved with effort and in a fair fight, like the one that got our team in the first leg of the tie.

"That celebration focused on congratulating our goalscorer in that game, whose career as a youth squad in the entity is a pride for our fans. We consider that the declarations of Busquets are totally contrary to the values of respect in football and can be generators of violence and intolerance."

Barcelona will face Valencia in the final four of the competition, with Leganes and Sevilla paired together in the other semi-final.