Gerard Pique has declared that Spanish referees have a pro-Real Madrid bias after the differing fortunes of the two sides in their Copa del Rey ties this week.

Barcelona lost 2-1 to Athletic Bilbao at San Mames on Thursday night, and Pique felt two decisions went against his side.

Two penalty claims - one involving Pique himself while the score was still 0-0 and then a poor challenge on Neymar just before half-time as Barca trailed 2-0 - were turned down by officials.

"The penalty to Neymar was very clear and the one with Gorka [Iraizoz] on me, too, but we already know how this works," Pique told Gol T after the game.

"We already saw what happened yesterday with Sevilla-Madrid and in recent times. We want to play football and not roulette, which is what these decision are creating."

Pique's claim is somewhat weakened by the fact that Athletic finished the game with nine men after referee Fernandez Borbalan sent off Raul Garcia and Iturraspe.

Nevertheless, he clearly believes decisions also went in Real Madrid's favour during their 3-0 win over Sevilla at the Bernabeu on Wednesday.

Pique later highlighted two polls the Madrid-based public television channel Estadio TV had posted on Twitter in the past month.

One asked whether Barcelona had shown a lack of respect to Hercules for resting Pique and the attacking trio of Lionel Messi, Luis Suarez and Neymar in a previous round of the Copa del Rey last month.

The other, posed last night, asked which side the referee had harmed more: Barcelona or Athletic.

"A couple of questions of public service television in less than a month... Congratulations @EstadioTVE," Pique tweeted.