Champions Barca have 87 points while Real are third in the Liga standings with 72 after 35 games.
MF Ivan Rakitic, 8 - The Croatian was Barca's hardest worker and most useful player in midfield, distributing the ball well and battling hard.
Madrid were stamping their authority on the contest, Ronaldo heading over and drilling wide either side of being denied at close range by Marc-Andre ter Stegen.
Barcelona has three matches left to become the first team to go unbeaten in the competition since the 1930s, when it consisted of 10 teams compared to 20 now. He could not be blamed for either of Madrid's goals.
With Barcelona already Spanish league champion and Madrid focused on its Champions League final later this month, it was supposed to be the most low-key "clasico" in years. In the end, however, the result was probably fair and Madrid felt they could have ended Barcelona's unbeaten record in La Liga.
Messi received a yellow card in the 45th minute for a poor slide into Sergio Ramos. It was clear that Marcelo baited him into lashing out, and baited the referee into showing a red card. Bale received a pass from Marco Asensio on that possession.
"We had a good opportunity to win today, clearly, we had a lot of chances to score, especially in the first half".
The nine-time LaLiga champion is expected to complete a switch to the Chinese Super League and said he is struggling to cope with the physical challenge of big matches.
Real Madrid wasted the opportunity to cut the deficit to second-placed Atletico Madrid, who were stunned by Espanyol 0-2 earlier in the day.
Alaves routed Malaga 3-0, and Getafe beat Las Palmas 1-0.