Cristiano Ronaldo gave Los Blancos a 19th-minute lead when he cut on to his right foot and drilled in his 43rd league goal of the season.
Sevilla missed a host of first-half chances, with Jose Antonio Reyes guilty of the worst of them.
And Sevilla were dealt a blow early in the second half when Coke's clearance ricocheted in off Benzema for Real Madrid's second.
But there was no doubt about Benzema's second, his 31st league goal of the season, as he met Sergio Ramos's cross with a diving header - meaning Barcelona must avoid defeat at Rayo Vallecano later on Sunday to prevent Real being crowned champions.
Real Madrid were looking to gain solace from their bitterly disappointing Champions League exit to Bayern Munich on Wednesday with victory over Sevilla in La Liga. Starting this game seven points clear of Barcelona, Los Blancos would take a huge step to the title with victory.
But they nearly fell behind early on when Ivan Rakitic slammed the ball into the net, only for Alvaro Negredo to be penalised for an innocuous challenge on Pepe in the build-up.
Instead, the hosts drew first blood when Ronaldo scored his 43rd Liga goal of another remarkable season for the Portuguese. Collecting Benzema’s pass, Ronaldo cut inside Coke’s despairing challenge and fired a low effort beyond Javi Varas.
Sevilla responded well to the early setback, and created three superb chances in five minutes. The first fell to Reyes, who could only find Iker Casillas with a tame shot before Jesus Navas blazed over after he was picked out by Reyes’s pinpoint through ball. Negredo went close minutes later when he chipped Casillas, but the ball dropped just over the bar.
That was as good as it got for Sevilla as Real cranked up the pressure and could have doubled their lead before the break, but Ronaldo’s low effort from an indirect free-kick inside the Sevilla box struck the inside of the post.
But Real effectively ended the match as a contest four minutes into the second half when Benzema was the beneficiary of a fortunate deflection. Angel Di Maria picked out Benzema with a low cross, only for Coke’s attempted clearance to deflect in off the Frenchman.
Sevilla barely had time to regroup and it was 3-0, with Benzema capping a fine counter-attack with a finely-taken header. Marcelo robbed Reyes of the ball and set Ramos free down the right wing. The Spaniard’s marauding run allowed him to cross for Benzema, whose diving header beat Varas.
The second half was less fraught than the first as Sevilla, who have now taken points on only three of their last 24 visits to the Bernabeu, accepted their fate and the Champions-elect strolled to their 29th league win of a prolific season.
Jose Mourinho’s side, who travel to the San Mames to face Athletic Bilbao on Wednesday, are unbeaten in 19 league games and will be crowned Champions on Sunday if Barcelona lose at Rayo Vallecano on Sunday night.