It capped off a great night for Mikel Arteta's side as they extended their lead to five points at the top of the Premier League.
For Brentford, it was more away day misery but they can take solace from the fact they pushed the Gunners far despite playing an understrength XI.
They reverted to a back-five, with Nathan Collins - a booking away from suspension - dropping out of the starting XI. Kristoffer Ajer and Ethan Pinnock joined Sepp van den Berg in central defence, with Rico Henry replacing Aaron Hickey.
They made the worse possible start when Arsenal took the lead after 11 minutes through Mikel Merino. Noni Madueke cleverly played in the overlapping Ben White, whose first-time cross found the Spaniard who headed past Caoimhín Kelleher to give the Gunners the lead.
Mikel Merino celebrates scoring Arsenal's first goal in their 2-0 win over Brentford. _(Image: PA)_
Madueke, in for Bukayo Saka, looked threatening in attack every time and he almost doubled Arsenal's lead soon after neat footwork saw him jink his way past several Brentford players but Caoimhín Kelleher saved his tame effort.
Brentford did not have much of a sniff in an attacking sense but they had a glorious opportunity to equalise when Kevin Schade's header was superbly tipped on to the bar by former teammate David Raya.
Madueke and White were enjoying a good relationship on the right-hand side and their good work almost once again came to fruition but Gabriel Martinelli's effort was too high to trouble Kelleher.
The winger thought he finally had his league goal for Arsenal from Declan Rice's low cross but Henry superbly denied him with a well-timed interception.
The second-half was a drab affair though Brentford started it on the front foot, forcing a succession of corners albeit to no avail.
Arsenal came close to doubling their advantage when Rice's curling effort was parried by Kelleher, but Merino was somehow unable to turn in the rebound.
Another chance went begging when Riccardo Calafiori's shot was parried, but Saka was unable to turn in the rebound.
Bukayo Saka celebrates after scoring Arsenal's second goal over Brentford. _(Image: PA)_
He would make amends when his shot went looping in over Kelleher, who got a hand to his effort, sealed Arsenal's victory despite making hard work of it.
The Bees continue their North London tour with a trip to N17 this Saturday, where they'll be looking to pile more home misery on their former head coach Thomas Frank and Tottenham Hotspur.
**Attendance:** 60,110