Rovers suffered a first defeat of
After taking an early two-goal lead thanks to goals from Bradley Dack and Danny Graham, the Bees scored five goals without reply, with the highly-rated Ollie Watkins bagging two of them.
In truth, the scoreline didn't reflect the game, with Rovers looking the most likely team to win the game after the hosts made in 2-2.
But an error from David Raya handed them a simple third goal, and, hunting down an equaliser, Rovers were ultimately picked off.
Both sides named an unchanged starting XI from their last Championship outings, meaning Elliott Bennett, who started for the 350th time in his career, took the captain's armband in place of Charlie Mulgrew.
The visitors were handed a dream start to the encounter as a flowing move ended in the in form Adam Armstrong crossing low to Dack, who swept home into the bottom corner.
It was the first move of the game for either side, and the second one at the other end almost ended in a Brentford equaliser, but Raya managed to palm behind a bouncing effort from Said Benrahma.
But things got better for Rovers soon after as a pinpoint Harrison Reed free kick found Graham, who planted an exquisite header beyond Dan Bentley and into the top corner.
However, five minutes later and the Bees were back in it as fine play from Kamohelo Mokotjo fed Benrahma, who committed Jack Rodwell before tucking into the bottom corner to breach a previously resolute Rovers backline.
The goal didn't appear to phase Rovers too much, and Graham lashed wide after Julian Jeanvier's poor clearance fell into his path.
Graham was involved again on the half hour mark when his cross was met by Armstrong, but after beating Bentley, Rico Henry was there to flick his effort over the upright.
From thge resulting corner, Reed's centre was missed by Bentley, but Darragh Lenihan's header flew into the 1,300+ Rovers fans behind the goal.
The game was open, and Benrahma's wicked free kick had to be turned onto the bar and away from danger by Raya.
Armstrong's bouncing free kick forced Bentley into a low save on the stroke of half time as Rovers went into the break the stronger, but there were concerns for Dack, who couldn't finish the first 45 minutes following a cynical challenge from French defender Yoann Barbet.
The Bees made a change at the break, with the impressive Henry being replaced by Moses Odubajo in the left wing position.
And just a moment into the half, Odubajo was fouled outside the box, and from the resulting free kick from that man Benrahma, Ollie Watkins' strike was straight at Raya.
The visitors' first opportunity a moment later when Dack's dink found Lenihan at the back post, but his header was clutched in the air by Bentley.
After Bees top scorer Neal Maupay smashed into the side netting, Dack's afternoon was done, as was Graham's, with the two goalscorers being replaced by Craig Conway and Joe Nuttall.
You felt the goal was coming, and come it did as a short free kick was played to Watkins, who rifled low into the bottom corner from the edge of the box, to equalise for the hosts.
The introduction of Ben Brereton seemed to galvanise Rovers, who improved after he replaced Corry Evans, but the hosts dealt a suckerpunch with sixteen minutes remaining.
After Maupay's strike looped up into the air, Raya came to claim the ball, missed it, and that allowed Watkins to head the ball into an unguarded net and complete the turnaround.
There was almost a susprising scorer as Rovers searched for an equaliser, with Amari'i Bell's flick flying narrowly past Bentley's right-hand post before Brentford killed off any chance of the visitors equalising.
A well worked move saw Maupay sneak in behind the Rovers backline before sliding the ball past Raya with 11 minutes remaining.
There was still time for a fifth for the Bees, with substitute Sergi Canos being fed by Watkins before smashing into the top corner in added time.
Brentford: Bentley, Henry (Odubajo, 46), Maupay, Watkins, Mokotjo (McEachran, 85), Sawyers (c), Benrahma (Canos, 80), Dalsgaard, Jeanvier, Konsa, Barbet.
Unused substitutes: Daniels, Dasilva, Ogbene, Sorensen.
Goals: Benrahma, 13, Watkins, 59, 74, Maupay, 79, Canos, 90
Booked: Barbet, 45
Rovers: Raya, Bennett (c), Rodwell, Lenihan, Bell, Evans (Brereton, 62), Travis, Reed, Dack (Conway, 52), Armstrong, Graham (Nuttall, 52).
Unused substitutes: Leutwiler, Williams, Smallwood, Rothwell.
Goals: Dack, 2, Graham, 8
Booked: Lenihan, 70
Referee: Andy Davies