Real Madrid have moved closer to securing the La Liga title as a Sergio Ramos penalty gave them a 1-0 win away to Athletic Bilbao for a seventh consecutive victory.
The hard-fought win took Zinedine Zidane's side on to 77 points after 34 games, seven clear of second-placed Barca who visit in-form Villarreal later on Sunday.
Athletic's San Mames is one of the toughest away trips in Spain and Real faced another gruelling match even without any fans in the stadium, as the Basques continually closed them down and subjected them to their usual aerial bombardment.
Yet just as in Real's last match against Getafe, the breakthrough came from the penalty spot, and Ramos once again showed nerves of steel by firing into the bottom corner in the 73rd minute to score a fifth goal in seven matches.
Zidane said it was unfair that his side were constantly being accused of benefiting from favourable refereeing after the decisive penalty separated the sides at the San Mames.
While penalty decisions went Real Madrid's way in recent victories over Valencia and Real Sociedad, Zidane dismissed the suggestion that the title was being decided on marginal calls.
"It's easy to ... talk about controversies but that's not the case, we are doing phenomenally well. We are giving everything on the pitch and we deserve everything we are achieving," Zidane told a virtual news conference.
"I don't like to get involved in these discussions but what I cannot accept is hearing that we are top of the table because of referees' decisions.
"We deserve more respect for what we are doing and I'm tired of people saying we are winning because of referees."