Ernesto Valverde's side had moved provisionally 12 points clear of second-placed Atletico by beating Leganes 3-1 at Camp Nou on Saturday and the squad will have been watching their two closest rivals with interest on Sunday.
A win for Real would have ended Atleti's slim hopes of claiming the title and that looked likely as Cristiano Ronaldo finally broke the deadlock with a fine finish after 53 minutes, slotting home an excellent Gareth Bale cross from the left.
But Antoine Griezmann levelled just a few minutes later and the game was back to where it started. And that is also how it remained despite opportunities at both ends.
For the fifth season in a row, Real failed to beat Atleti at home in La Liga, with this draw coming exactly one year after the two teams tied 1-1 in last season's corresponding fixture. Prior to that, Atletico had won the previous three.
Ronaldo's remarkable run in front of goal continues and the Portuguese has now netted 40 goals this term, with 20 of those coming in the last 10 games (with at least one strike in each of those).
The 33-year-old was withdrawn after 63 minutes for a rest ahead of Madrid's Champions League quarter-final second leg against Juventus at the Bernabeu on Wednesday and was an animated observer from the bench as Sergio Ramos twice came close to a late winner – once with a free-kick pushed over by Jan Oblak and then with a header from the resulting corner.
Madrid had more chances, although Atletico also threatened on a number of occasions and the lively Griezmann became the first player this century no score in three consecutive Liga games for a visiting side at the Bernabeu.
But the result is of little use to Atletico, now 11 points behind Barca with just seven rounds of the Primera Division remaining. With the Catalans still unbeaten, making up that deficit appears impossible now.
And for Real, the draw is not much good either. It leaves Los Blancos four points adrift of Diego Simeone's side, while they will now drop to fourth position if Valencia beat Espanyol later on Sunday.
Meanwhile, without even stepping onto a football field on Sunday, Barcelona are closer to the prize that rewards the season's most consistent club. Following Sunday's derby draw, La Liga is now virtually won for the Blaugrana.