A Branislav Ivanovi? header a third of the way through the half gave the League One side a brief scare, but it was Oscar who came closest by far, the young Brazilian finding himself with the ball at his feet deep within the penalty area before losing his footing slightly and sending his shot bouncing off the outside of the post.
Brentford fans were left screaming in disapproval as the half came to a close when Italian striker Marcello Trotta broke past John Terry and calmly tucked the ball away into the corner of the goal, before turning to find referee Neil Swarbrick pointing for a free-kick on the edge of the penalty area after David Luiz had fouled Adam Forshaw just moments earlier.
Chelsea seemed to step it up a gear upon returning from the dressing room after half time, and goalkeeper Moore once again came to the rescue of the Bees, superbly saving another strong header from Ivanovi? and diverting it away from the fast approaching Demba Ba.
However, Juan Mata finally made the Blues pressure count and put the home side ahead after fifty-five minutes when he picked up a long ball on the edge of the area and fired into the far corner of the net, easing the fears of the Chelsea faithful.
Thirteen minutes later, a deft backwards flick from Oscar a mere feet in front of goal evaded at least two Brentford defenders and Moore on the line and doubled their lead, and from then onwards Chelsea were firmly on the front foot and in full control.
It then took just three minutes for the hosts to make it 3-0 with Mata, who, alongside Oscar, had been critical in the heart of the Chelsea midfield from the start until his substitution for Yossi Benayoun with just under fifteen minutes to play, lightly chipping in a beautiful cross to Frank Lampard, the veteran making up for his questionable attacking performance in the first half with a volleyed effort that extended his Chelsea goal scoring tally to 199, now only three behind Bobby Tambling.
With Brentford well and truly beaten, the home side were able to surge forward in numbers, and John Terry, back in the first team for the first time since their 3-2 defeat to Newcastle United at the start of the month after suffering a setback with his knee injury, marked his return in fine fashion with a headed effort that put his side 4-0 up and comfortably through to the fifth round with little under ten minutes to go.
The enigmatic David Luiz failed to see a 4-0 lead as a chance to play it safe and run out the clock, and almost saw himself dismissed in the eighty-fifth minute after he cynically clattered into substitute Jake Reeves, the Brazilian keeping his eyes off the ball and firmly on the nineteen-year-old as he ran shoulder first into the youngster as he attempted one last attack for Brentford. Luiz got off with just a yellow card from referee Swarbrick, but, upon closer inspection, it could have easily warranted a far more harsh punishment.
A tale of two halves ended in an emphatic victory on paper for Chelsea, but, as those who were heartily singing the praises of former manager Roberto Di Matteo in the sixteenth minute know all too well, the scoreline doesn’t always tell the story, and for all of the silky smooth moves of players like Mata and Oscar that paper over the cracks, Rafa Benítez’s side are still missing something crucial.
If they are to challenge the two Manchester clubs for another Premier League title any time soon, a lot of work still needs to be done.