Frank: Keep off my BMW
after 19 minutes as Mathias Jensen’s low free-kick was seized upon by sharp movement from Benrahma, who stroked the ball into the corner of the net.
Four minutes later, Brentford were given a helping hand as they extended their advantage.
Geoff Cameron’s attempt to head the ball back to keeper Joe Lumley fell well short and Mbeumo smartly turned the ball home for the second.
The home side had several more chances before Watkins headed in the third, swooping at the far post to head in after Ethan Pinnock had risen to head a Jensen free-kick across the goal.
Former Bees boss Mark Warburton tore into his QPR players at the interval and they responded as Nahki Wells latched on to a Bright OsayiSamuel cross on 62 minutes to pull one back.
But Brentford keeper David Raya’s save from Ebere Eze cut hopes of a fightback.
There was still time for Watkins to blaze wide for a possible Brentford fourth.
Warburton said: “We had a few heated words at halftime. My boys probably gave that one away.
“First half was not QPR – unacceptable. We lost first contacts, we lost duels, we did not do our jobs at set pieces.
“We got the goal we wanted. Then we had a chance. If that goes in, the stadium gets nervous and we are on the front foot.”
BRENTFORD QPR 6 ........ Shots on Target ......... 2 5 ........ Shots off Target ......... 2 8 ................ Corners ................ 0 8 .................. Fouls .................. 17 3 ............... Offsides ................. 2 71.1..Passing Success % .77.7 402 ...... Total Passes ........ 439 48.3 .... Possession % ...... 51.7 53.5..Territorial Adv %..46.5