Cristiano Ronaldo, Luka Modric and Gonzalo Higuain, with his second of the game, netted in a six-minute spell and substitute Karim Benzema notched a fifth goal at the end to leave coach Jose Mourinho’s side in second place with 61 points and 10 games left.
French winger Antoine Griezmann scored twice, the second with a spectacular volley, as Real Sociedad battered visiting Real Valladolid 4-1 to go fourth with 47 points.
Sociedad are 10 points behind third-placed Atletico Madrid, who visit Osasuna on Sunday, and two ahead of Valencia who climbed to fifth with a 3-0 win over 10-man Real Betis.
Five minutes from time Betis defender Paulao turned a Sergio Canales cross into his own net and Jonas completed the scoring with a curling shot at the end.
After a tight opening period Sociedad scored three times in the last 13 minutes of the first half, the 21-year-old Griezmann tucking away the first from close range in the 33rd.