Real Sociedad goalkeeper Alex Remiro made a string of fine saves to frustrate Real Madrid in a 0-0 draw at the Santiago Bernabeu on Sunday, leaving Barcelona five points clear at the top of La Liga.
After the Catalans beat Girona on Saturday Madrid needed to win to stay three points behind their rivals in the title race, but Remiro ensured otherwise, keeping third-place La Real on the champions' tail.
Vinicius Junior had three good chances repelled by Remiro among other Madrid openings, as Carlo Ancelotti's side sparkled but failed to find the goal their performance deserved.
The draw continues a mixed start to 2023 for Real Madrid, slipping further behind Barcelona in the league and losing against them in the Spanish Super Cup final, but reaching the Copa del Rey semis on Thursday with an extra-time win over Atletico Madrid.
"It was one of the best games we've played this season," Ancelotti told reporters.
"It's true Barca are doing very well, but the season is very long, January is very complicated, but the team have progressed a lot in all areas, in defence, attack, physically.
"The players are starting to improve, the injured players (will return), so we are confident for the coming months, we can get stuck into it in the second half of the season."