Barca chief wants Clasico replay if Yamal 'ghost goal' call wrong
The champions fell to a 3-2 defeat against Real Madrid at the Santiago Bernabeu on Sunday in a match which featured multiple controversial incidents, leaving their arch-rivals 11 points clear at the top of La Liga.
The most debated was 16-year-old winger Yamal's first-half flick from a corner which may have crossed the line before Madrid goalkeeper Andriy Lunin pushed it away.
Without goal-line technology in Spain, officials used VAR to try and confirm if the ball had crossed the line but could not be certain it had and so play continued with the score level at 1-1.
Laporta demanded the Spanish football federation and the refereeing committee send Barcelona all footage of the incident and audio recordings of the officials' conversations.
"If, once the documentation has been analysed, the club understands that there was an error in the assessment of the play, as we think there was, we will take all the necessary steps to reverse the situation, without ruling out any legal action that may be necessary," said Laporta in a video published by Barcelona.
"If it is confirmed that it was a legal goal, as we believe it was, we will go further and ask for a replay of the match, as has happened in another European match due to a VAR error."
Laporta was referring to a match between Anderlecht and Genk in January in the Belgian top flight which was initially scheduled to be replayed because of a misapplication of the laws of the game, but in the end it was ruled that Anderlecht's 2-1 win would stand.
Barcelona coach Xavi Hernandez said Sunday it was a "disgrace" that Spanish football did not have goal-line technology.
Laporta also criticised a general "misuse" of VAR, saying there appeared to be "contradictory criteria" for its intervention depending on the teams involved.
Barcelona had two penalty appeals turned down during the Clasico defeat for what they said were fouls on Yamal and Fermin Lopez.