Real Madrid won seven consecutive competitive matches without conceding for the first time in their history thanks to their 2-0 win over Granada on Saturday.
Cristiano Ronaldo struck his 14th league goal in his last 10 appearances just before the hour and Karim Benzema made sure with 15 minutes remaining.
Thed victory opens up a two point-gap over rivals Barcelona and Atletico Madrid, who have a game in hand, at the top of La Liga.
Ronaldo was denied on the stroke of half-time as his overhead kick from seven yards was brilliantly kept out by Ricardo.
Luka Modric and Benzema both wasted chances early in the second half, but in the 56th minute Ronaldo finally broke the deadlock.
The forward receiving a pass from Modric inside the penalty area, he was allowed to turn and fired low beyond Ricardo to relieve the pressure inside the Santiago Bernabeu.
And, after Ronaldo had seen a free kick hit the crossbar, Madrid doubled their lead in the 75th minute, Marcelo squaring a pass to Benzema to turn home from close range.