Gerard Pique claimed referees influenced the outcome of the La Liga title race as the Barcelona defender again called for video technology to be introduced.
The Spain international has criticised officials on several occasions this season, both in person and through social media, and was fined €3,000 in March for some of his remarks.
Pique this week urged La Liga to introduce the Video Assistant Referee (VAR) technology so as to reduce the risk of officials making mistakes that could cost teams important results.
And the 30-year-old has gone as far as to say that Real Madrid's title triumph was made easier due to refereeing errors, even though he concedes that Barca did not play well enough consistently to deserve to win.
"The referees have been able to influence things; I'm not going to draw up a list of when we have been favoured or when it's happened to our opponents," he told a news conference ahead of Saturday's Copa del Rey final against Alaves.
"In the end, Madrid won, and we have to turn the page.
"It's still clear that we should implement VAR, which would have been decisive, but there were games where we did not reach our best level. There's no point throwing criticism around. To win the league, you have to be infinitely better.
"With VAR, the refereeing errors will be reduced and therefore we'll all be on equal terms. It will take a lot of the responsibility from the referees on vital decisions, like penalties and goals, and they will make far fewer mistakes.
"I'm not looking for excuses but sometimes it feels as though you are penalised by more than just the score."
Barca face Alaves at Vicente Calderon on Saturday, looking to win the Copa del Rey for the third year in a row.
It would mark a victorious end to Luis Enrique's time in charge, with the head coach having confirmed he will leave his position at the end of the season.
Pique praised the impact of the 47-year-old during his three years at the helm at Camp Nou and said his cool approach towards the media was not one he used with the players.
"He's been one of the best coaches in history. He deserves to win the final," he said.
"The easiest thing would be to focus on the titles but for me it's been the way he does things with us [that stands out]. Maybe he didn't have the best relationship with you [the media] but he won over all of us. They've been three amazing years."
Luis Suarez will miss the match due to suspension but Pique has backed Paco Alcacer to impress in his absence.
"We're a team that can't think about absentees. I'm sure that Paco will have a great game," he added.