Real Madrid went to the top of La Liga thanks to a hard-fought victory at Real Sociedad.
Zinedine Zidane’s side are level on points with Barca, who drew 0-0 with Sevilla on Friday, but go top because of their superior head-to-head record.
Sergio Ramos’ penalty after the lively Vinicius Jr was fouled gave the visitors the lead.
Madrid – who have only won one La Liga title since 2012 – are now eight victories away from winning the league.
Barcelona host Athletic Bilbao on Tuesday with Real at home to Mallorca the next day (both 21:00 BST kick-offs).