New signing Marco Djuricin took just half an hour to score his first Brentford goal as they led at the break at Elland Road.
The on-loan Red Bull Salzburg striker provided the finishing touch from Alan Judge’s pass after a counter-attack.
The pair had combined a moment before the goal, with Djuricin setting up Judge but he fired over the bar.
Austria international Djuricin was involved from the off and Brentford went close in the opening minute, Gaetano Berardi clearing off the line to deny Konstantin Kerschbaumer.
At the other end, Bees keeper David Button saved from Charlie Taylor from distance and former Brentford midfielder Sturt Dallas curled a right-footed shot well over.
As well as Djuricin, two further Brentford signings were named in the squad, though Liverpool loanee Sergi Canos and former Shrewsbury midfielder Ryan Woods had a watching brief from the bench.
Subs: Bonham, Hofmann, Woods, O’Connell, Barbet, Udumaga, Canos.