Frank Lampard scored his 199th goal for Chelsea as the FA Cup holders overcame spirited resistance from Brentford before crushing the third-tier side 4-0 in their fourth round replay at Stamford Bridge on Sunday.
Second-half goals from Juan Mata, Oscar, Lampard and captain John Terry secured Chelsea a fifth round tie at Championship (second division) Middlesbrough on February 27.
England midfielder Lampard, whose Chelsea future remains unresolved with his contract expiring at the end of the season, tucked away a simple volley on 71 minutes to edge closer to Bobby Tambling's all-time club record of 202 goals.
The goal prompted Chelsea fans to chant 'sign him up' as billionaire owner Roman Abramovich, sat with hands deep in his pockets, forced a wry smile high up in the stand.
Interim manager Rafael Benitez said: "The team was doing well and Frank Lampard is scoring goals, which is good for him and good for us."
Chelsea twice had to come from behind to earn a 2-2 away draw in their first encounter and were again sluggish in the first half against their fellow Londoners.
Mata finally broke Brentford's resistance on 54 minutes when he latched on to Demba Ba's flick from a long Petr Cech clearance and drilled in a left-foot shot from 20 metres.
Oscar doubled the lead 14 minutes later from Branislav Ivanovic's cutback, scoring with a deft flick, and Lampard quickly added a third from Mata's cross. Terry headed in at the far post, this time from Oscar's curling delivery, to make it 4-0 on 81 minutes.
"First half they made it very difficult, they sat very deep. Once we got the first goal, the second and third were sure to come," Terry, returning after missing two matches with an inflamed knee, told ITV.
Terry said a British newspaper report on Sunday that he and Benitez were involved in a dressing room bust-up were "complete rubbish".
"There are stories today in the paper but it is complete lazy journalism," the defender said, referring to a Sun newspaper story headlined "War".