Luis feels their financial advantage hurts the rest of the competition.
"We are talking about two teams that no-one can compare to," the Brazilian left-back told AS.
"It is a tremendous injustice that the league is so unbalanced. That Barca and Madrid have budgets that are so immensely greater increases doubts that this is the best league in the world.
"It is more interesting lower down in the table than it is in the fight for the title."
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