Sergio Ramos put Los Blancos back in front after 33 minutes when he nodded in Ozil's corner.
Uche came close to drawing the visitors level for the second time in the match, but his left-footed drive hit the sidenetting from a tight angle.
Madrid came out for the second half in explosive fashion as Gonzalo Higuain took a touch before firing into the net from 12 yards to make the score 3-1.
Benzema grabbed his second of the match two minutes later when he collected Ozil's cross-field pass to rifle in from inside the area.
Cristiano Ronaldo nearly made it five on 50 minutes, but his low shot flew inches wide.
The Portuguese winger put another shot marginally wide with 20 minutes to go, before Jose Callejon's effort was comfortably saved.
Ronaldo did get on the scoresheet with two minutes to play when his shot flew in from 18 yards.
Rivals Barcelona can cut the gap at the top of the table back to three points on Sunday when they face Espanyol in the Catalan derby.