Real Madrid outplayed Barcelona for large parts of Wednesday's La Liga clash but were unable to make their dominance count and the Clasico ended goalless to leave the Catalans top of the standings on goal difference.
Both sides had shots cleared off the line and Gareth Bale did put the ball in the net after the interval but his strike was narrowly ruled out for offside and the fixture ended scoreless for the first time since November, 2002.
The draw left Barca top on 36 points after 17 games with Real also on 36, five clear of third-placed Sevilla.
The game was rescheduled from Oct. 26 due to the political turmoil that gripped Catalonia after separatist leaders were given lengthy jail sentences two months ago and was played amid a protest in favour of independence near the stadium.
Loud chants of "independence" and "freedom" greeted kick-off while many supporters held up flags reading "Spain Sit and Talk" distributed by protest organisers in a call for dialogue between the central government and Catalonia.
Local police reported confrontations between officers and protesters outside the ground while play was briefly stopped in the second half when a number of beach balls were thrown on to the pitch amid more chants for freedom for the jailed leaders.
The action on the pitch did not quite live up to the billing or the tense atmosphere in the stands as Barca failed to get going throughout the game and Real bossed the first half.
Zinedine Zidane's side fired 12 shots at the hosts' goal before the interval, coming closest with a Casemiro header which Gerard Pique scrambled off the goalline, while they also had two penalty appeals waved away for challenges on Raphael Varane.
Ramos said his side were unfortunate not to earn a spot-kick.
"Today we saw a great Real Madrid side with a lot of character which is exactly the image we wanted to give. We went out to try and take the ball off them and we created a lot of chances," he told reporters.
"We watched the penalty appeals at half-time and they seemed pretty clear, they are both penalties but we can't change that. VAR is there to help but today we didn't get that bit of luck."
Casemiro added: "On the pitch I wasn't sure, but when we saw Varane's leg at half-time and the video, there were no doubts that it was a penalty. We go home a bit angry because at least they could have looked at it again. Then you can give a penalty or not, but at least look at it."
Barca looked short of ideas, with Lionel Messi being their only source of inspiration.
He could have broken the deadlock in the first half but Madrid captain Sergio Ramos slid to the floor to block his goal-bound shot.
Messi later teed up Jordi Alba with a scooped pass but the defender fired just wide, while Barca's all-time top scorer was uncharacteristically sloppy at times and miscontrolled a clear opportunity to strike at goal in the second half.
Midfielder Ivan Rakitic admitted Barca had struggled for parts of the match.
"Real Madrid had a lot of chances in the first half, it was tough for us but then we had a few opportunities. It was a game that could have been decided by the odd goal but it wasn't to be," he said.
"We're happy with how we played, but we just lacked that final touch of quality."