Spanish winger Jota with two second half goals in four minutes added to Yoann Barbet's first half strike as the Bees outclassed the Hoops, whose goal came from Joel Lynch.
The hosts broke the deadlock after the half hour when centre back Barbet smashed Jota's corner into the roof of the net on the half volley.
Brentford dominated the first half possession-wise, but it was Rangers who created the more clear-cut chances with Matt Smith a physical threat.
But Jota made it two on the hour mark when he sent Rangers keeper Alex Smithies the wrong way from the spot after Maxime Colin was scythed down in the box by Nedum Onuoha.
Lynch gave the visitors hope two minutes later when he glanced home Luke Freeman's corner at the near post.
But it was only a temporary reprieve. Jota made it safe seconds later with a goal of the season contender as he took Barbet's drilled diagonal ball in his path, left former Bees Jake Bidwell for dead with his first touch and slotted home coolly beneath Smithies to send the home fans delirious.
From the start Brentford started on the front foot, top scorer Lasse Vibe's sharp turn and drive finding the side netting.
The visitors' big striker Matt Smith caused problems and when his header was diverted towards goal by Lynch it looked odds on certainty but for keeper Daniel Bentley's full length stop.
Lynch went close again just before the opening goal, racing on to Smith's headed flick-on only to fire well wide on the volley.
After Barbet's goal, Brentford were switching play effortlessly but their final ball lacked the quality to breach a Rangers defence and add to their score.
Left back Rico Henry almost extended the hosts' lead 10 minutes before the break, but his low cross shot was well saved by Smithies.
Rangers' best chance of the first half came just before the interval when Bidwell crossed for Smith, whose powerful header was parried into the path of Conor Washington by Bentley only for the striker to blaze wide.
Massimo Luongo's long range effort bounced harmlessly off the top of the bar to leave the Bees lead intact in time added on.
After the break Rangers looked dangerous and might have equalised when Lynch's far post header appeared to loop over the Brentford defence only to be headed off the line by Barbet, much to the fierce protests of the visitors who insisted it was over.
But as Ian Holloway's side pressed, Brentford cut them open at the back and Vibe was only denied by a smart Smithies stop.
A five-minute period then settled the game. Jota scored his penalty on the hour mark, only for Lynch to give his side some hope just two minutes later. However Jota's wonder goal in the 64th minute sealed the points.