Picking up from where they left off in the first leg, Madrid raced to a 2-0 lead against Barca in the first half and made easy work of protecting their advantage.
Los Blancos went Lucas Vazquez and Marco Asensio in attack against Barca, who switched to three at the back and Lionel Messi in a front two with Luis Suarez.
Cristiano Ronaldo’s red card for pushing the referee at Camp Nou warranted a five-match ban, but the capital giants looked liberated in their first game without the Portuguese.
Barely a ball was kicked when Asensio broke clear down the left and pulled the ball back for the returning Luka Modric, but his shot with the outside of his boot was charged down by Samuel Umtiti.
Nonetheless, the €4.5m signing from Mallorca did it again, unleashing a rocket past Marc-Andre ter Stegen for the second Clasico running.
Luis Suarez, meanwhile, sprung Los Blancos’ high line and got to Keylor Navas’ near post, but none of his teammates were able to meet his cutback. The No 9 then hit a long ball on the half-turn but couldn’t keep his volley down.
Messi barely figured in the first half by his lofty standards, but he did manage to get in behind with only Keylor to beat, although the goalkeeper smothered the danger.
That would be short-lived, however, as Vazquez broke away down the right and teed up Toni Kroos, whose side-footer whistled inches wide of the right-hand post.
The winger then delivered a pinpoint cross for Benzema to head home, but a Blaugrana shirt just about got in the way of it.
With just over 10 minutes of the first half remaining, Vazquez suddenly cracked a shot at Ter Stegen’s goal, which struck the woodwork.
The cantera’s shooting boots may have evaded him, but Benzema was certainly wearing his as he spun Umtiti in the box from Marcelo’s low cross and slotted the ball home on the half-volley.
Vazquez almost made it 3-0 Madrid just before the break, coming into view from the right, but he fired straight at Ter Stegen.
A minute into the second half, Keylor made a great save down low to deny Suarez at the near post, but the Catalans’ optimism was quickly followed by Gerard Pique pulling up with a knock. The defender was replaced by Nelson Semedo for his competitive debut in a Barca shirt.
The visitors pushed on and were almost rewarded when Suarez teed up Messi, who took a touch before curling a shot onto the frame of Keylor’s goal.
Benzema, meanwhile, shimmied past Javier Mascherano and hammered a shot on target from Asensio’s flick, which Ter Stegen tips over, despite the German knowing little about his opponents’ effort.
Barca continued to plug away, and Keylor was a lucky boy as he missed Messi’s free kick and could only watch Gomes head wide of the far post.
Sergi Roberto’s daisy-cutter towards the end was pushed away by the Costa Rican, but only as far as Suarez, whose diving header on the rebound hit the post.