Nacho’s first-half opener for the hosts was cancelled out by former Madrid midfielder Wesley Sneijder early in the second period but Marcelo’s fine solo strike eight minutes from time sealed victory in the Santiago Bernabeu Trophy fixture.
Benitez named close to his strongest available line-up just five days before his new side kick-off their La Liga campaign away to Sporting Gijon, but Bale failed to fire and his late substitution was greeted by a smattering of whistles.
Real made a less than convincing start, Umut Bulut heading just wide before Lukas Podolski forced Keylor Navas into his first save of a busy evening.
Madrid did manage to break a two-game streak without scoring when defender Nacho headed home Luka Modric’s corner after 17 minutes.
Isco was inches away from doubling Real’s advantage with a lovely curling effort that clipped the bar before Bulut passed up a great chance to equalise when he blazed over from barely three yards out.
Bale endured another largely frustrating night as he too failed to find the target with an effort from distance and was met with boos from sections of the home support.
And even Cristiano Ronaldo’s eye for goal wasn’t in, the World Player of the Year spooning a glorious opportunity over from Jese Rodriguez’s fine cut-back with the last action of the first half.
Madrid were made to pay for that miss early in the second period when Sneijder levelled against his former side with a fine left-footed strike into the far corner.
Navas saved Rafa Benitez the embarrassment of going behind on his home debut with a stunning save from Sabri Sarioglu moments later.
Both sides then made a raft of substitutions, but there was one moment of real quality left to decide the game as Marcelo skipped past three Galatasaray defenders before prodding the ball home at the near post.