Real Madrid stumbled in a tight Spanish league title race after being held at home by Real Betis to 0-0 on Saturday.
Madrid was left two points behind leader Atletico Madrid, which can take a big step toward its first title since 2014 if it wins at Athletic Bilbao on Sunday.
Barcelona also has the chance to move ahead of the defending champion. Lionel Messi's side has two more games to play than its two title rivals, with its first coming at Villarreal also on Sunday.
The slip came three days before Madrid starts its Champions League semifinal against Chelsea in the Spanish capital.
In a toothless outing for Madrid under steady rain at its Alfredo Di Stefano Stadium, the closest the host came to scoring was Rodrygo's errant cross hitting the crossbar in the 55th minute.
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