The Frenchman went into the game having only scored twice in the semi-finals of Europe's premier club competition in his entire career, but silenced his doubters with two vital goals at the Bernabeu.
Real Madrid were the hot favourites to progress following their exploits in Munich last week, but they suffered a case of déja vu when Josh Kimmich struck early on in the second leg to lift hopes of a comeback, just as Mario Mandzukic did for Juventus in the quarter-finals.
With just three minutes gone the right-back found himself in the right place to pounce after Sergio Ramos failed to clear a cross from the right, slotting home from six yards.
1 May 2018
That lead didn't last long though as the hosts hit back. Marclo dug out a cross on the left and Benzema intelligently slipped away from his man at the far post to give himself the simple task of converting a routine header unmarked.
A common theme in the game was Bayern's frustration with the officiating, with the Bavarians twice seeing penalty appeals turned down before the break, first when Robert Lewandowski tangled with Ramos and again when Kimmich's cross struck the hand of Marcelo.
The Brazilian squandered a presentable opening for the home side when he dwelled on the ball after being slipped in on the overlap by Ronaldo, allowing defenders to pile back and clear his cutback.
The game saw James Rodriguez return to the Bernabeu for the first time since his summer departure and he fluffed his lines in incredible fahsion just after the half-hour mark, somehow blazing over with the goal at his mercy after Keylor Navas had denied Lewandowski.
Cristiano Ronaldo, quiet by his usual standards, saw a low effort well saved by Sven Ulreich as the game approached half-time, with the two sides going in level after an opening 45 that ebbed and flowed.
- Ulreich gift -
Bayern got the second period underway but within 60 seconds they had completely shot themselves in the foot. Ulreich made a complete mess of Corentin Tolisso's ill-advised backpass, contriving to miss the ball completely and presenting Benzema with the routine task of tapping the loose ball into the empty net to put the hosts ahead.
That goal meant that the visitors needed two goals to advance, but they responded well, with David Alaba forcing an impressive save from Navas down to his right.
Ronaldo ought to have made the game safe for Real with 54 minutes on the clock, only for the Portuguese to somehow side-foot Marcelo's inch-perfect cross over the crossbar at the far post when under no pressure whatsoever.
Just nine minutes later, Ronaldo was left to rue that miss even more as Bayern drew level. James made no mistake this time, reacting first to the loose ball after his effort was blocked to slip an effort through the legs of Navas from a narrow angle.
From there on in it was kitchen sink time for Bayern, but they came up against an inspired Navas, who made excellent saves to deny Tolisso and Thomas Muller as the game moved into its final knockings.
Raphael Varane and Sergio Ramos impressively repelled the aerial onslaught that Sandro Wagner's introduction brought with it as Real held firm to keep their dream of claiming an unprecendented third straight Champions League crown alive.
1 May 2018