The hosts avoided the competition's upset bug, with the floodgates opening in the second half as Juan Mata and Oscar led the charge in the fourth-round replay.
After a goalless first half, Juan Mata broke the deadlock before Oscar and Frank Lampard hit a one-two punch midway through the second half. John Terry wrapped up the scoring, as Chelsea advances to face Middlesbrough.
Terry had been recalled to the Chelsea starting XI after injury, while Victor Moses returned to the fold following his Africa Cup of Nations triumph. Fernando Torres’s replay-earning strike at Griffin Park did not stop him being dropped for Demba Ba, while Harry Forrester was unexpectedly benched by Brentford.
The game began evenly and the visitors, far from overawed, had chances early on, with Adam Forshaw’s long shot and Clayton Donaldson’s header wide. Chelsea had its own efforts but was also lucky not to lose a man when Gary Cahill clumsily caught Jonathan Douglas on the shin.
Using increasingly adventurous passing to open up space, the Blues came close on 26 minutes, with Oscar shooting on the slide when Brentford was caught out, but the Brazilian, unable to control the shot, hit the post.
Uwe Rosler’s men kept their heads, with the impressive Forshaw firing just past Petr Cech’s post. The Bees were later frustrated when Marcello Trotta put the ball in the Blues’ net, but referee Neil Swarbrick pulled play back for a David Luiz foul earlier in the sequence.
After halftime, the Blues continued to press, with Bees keeper Simon Moore reacting superbly to divert Branislav Ivanovic’s header from goal and out of Ba’s reach. The resistance broke five minutes later, however, when a long ball dropped to Mata. With bodies between him and the goalkeeper, the Spaniard shot across into the far corner and put home hearts at ease.
Brentford plugged away, but struggled for venom despite Forrester’s introduction and was broken decisively with 20 minutes to go.
Substitute Eden Hazard held the ball up while Ivanovic overlapped, with the Serbian then crossing low into the box where Oscar flicked toward goal. The finish evaded Moore, but Harlee Dean inexplicably stepped over it as it rolled over the line.
The knockout punch followed, as Mata ran into space on the left before pulling it back with class for Lampard on the edge of the box, the midfielder this time making no mistake for hsi 199th career goal with Chelsea.
With the Bees beaten and the mood calm, captain Terry had freedom to get forward, and he nodded in a fourth from Oscar's cross to mark his first-team return.