Hundreds of thousands in Catalonia have been protesting over Spanish police violence during Sunday's vote, during which almost 900 people were hurt.
Catalonia will proclaim the region's independence from Spain within several days, Catalonia's President Carles Puigdemonttold the BBC broadcaster. Spain's government and Constitutional Court had declared the referendum illegal.
Former Barca manager Pep Guardiola was among those to have criticised the decision to play.
Las Palmas, an offshore club from the Canary Islands, added their own charge to the affair by wearing Spanish flags on their shirts.
Barcelona's players, meanwhile, wore red and yellow shirts - the colors of Catalonia - before reverting to the club's normal strip for the match.
GettyThere were large-scale demonstrations in Catalonia after the vote
Pique, part of Spain's World Cup-winning squad in 2010, also added that he would retire from worldwide football if his stance on the matter was regarded a problem.
He said that he would present the results to the Catalan parliament.
"If not, I will not go".
Some people think that Catalonia still doesn't have enough freedom and power from the Spanish government and that it should be allowed to run itself completely.
"For a moment I couldn't believe it", he said.
Zeid, a Jordanian prince who goes by his first name, also urged Madrid to accept "without delay" the requests of two United Nations -mandated investigators on freedom of assembly and minorities to be granted access to visit Catalonia.
"It wasn't like that, but at least the whole world has seen it".
Separatist movements aren't rare anywhere, and Catalonians have supported one peacefully over time in a region that contributes nearly a fifth of Spain's GDP.
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