Brentford 2 Millwall 0
Thomas Frank got his first win as Brentford boss thanks to second-half goals from Sergi Canos and substitute Ollie Watkins.
Canos slotted home the opener on 48 minutes before Watkins came off the bench to put the Bees out of sight with a similar finish late on.
Brentford twice hit the bar, through Neal Maupay and the impressive Said Benrahma – who replaced Watkins in the starting line-up.
Benrahma rattled the frame with a vicious right-foot shot after cutting inside from the left, and the summer signing from Nice also went close with a free-kick.
At the other end, Daniel Bentley pulled off a good save to keep out Lee Gregory’s goal-bound header before the break.
And Millwall threatened in the second half, with Jed Wallace twice firing wide from distance, before Canos’s composed finish made it 1-0.
Maupay hit the bar from all of two yards and then flashed a shot wide from a tight angle before Watkins broke into the box and fired in the second.
Brentford (4-3-3): Bentley; Dalsgaard, Konsa, Mepham, Odubajo; McEachran, Sawyers, Yennaris; Canos (Watkins 72), Maupay, Benrahma (Judge 81)
Subs not used: Daniels, Dasilva, Clarke, Barbet, Carroll