Karim Benzema scored the only goal as Real beat Atletico in the Madrid derby to go six points clear at the top of La Liga.
The French striker converted Ferland Mendy's cross from six yards out to give Real a deserved win.
Fifth-placed Atletico, who have not won in five games, were disappointing, although Angel Correa hit the post.
Real could have won by more with half-time substitute Vinicius Jr forcing two saves from Jan Oblak.
Gareth Bale was left out of the squad despite being fit.
Zinedine Zidane's side are now unbeaten in 21 games and have won eight in a row - including a penalty shootout success over Atletico in the Spanish Super Cup.
Second-placed Barcelona host Levante on Sunday (20:00 GMT).
BDST: 1256 HRS, FEB 02, 2020