Brentford were beaten by a pair of late goals as a weakened Chelsea squeezed into the semi-finals of the Carabao Cup with a 2-0 win away from home.
The Blues took the sting out of the boisterous home crowd with largely sterile possession to begin the match, setting the pattern of a first half with chances short in quantity.
In their first competitive fixture for 12 days, Brentford sat in a 5-3-2 shell, waiting to pounce on a loose touch or pass from Chelsea's unfamiliar XI.
Rico Henry proved the hosts' most penetrative outlet at left wing-back, repeatedly haring beyond the debuting teenager Xavier Simons to tee up both Yoane Wissa and Mathias Jensen for close range headers aimed straight at Kepa Arrizabalaga.
Chelsea dominated possession and territory but struggled to carve out any opening of note. The Blues' first clear sight of goal fell to their brightest newbie, Harvey Vale, as the first half drew to a close. However, the 18-year-old followed the pattern of the match by steering his header into Alvaro Fernandez's grateful grasp.
A cagey first half was robbed of the intermittent bursts of Brentford breakaways as Chelsea firmly pulled up the handbrake after the interval.
However, the Blues continued to labour in front of goal themselves, eventually breaking the deadlock via Brentford's own skipper. Chelsea's substitutes combined in the final ten minutes to force Pontus Jansson's own goal as N'Golo Kante wriggled around a flurry of flailing legs to tee up Reece James for a fizzed cross that found its way past Fernandez.
Christian Pulisic beat Brentford's keeper to the ball inside the area just five minutes later, earning a penalty which Jorginho cooly converted to secure Chelsea's passage into the final four.
Brentford player ratings
1. Goalkeeper & defenders
Alvaro Fernandez (GK) - 4/10 - Lured into the unnecessary tackle that helped Chelsea double their lead.
Ethan Pinnock (CB) - 6/10 - Seemingly granted more freedom on his unnatural side of Brentford's back-three, Pinnock peppered a commanding individual defensive display with some raking cross field passes.
Pontus Jansson (CB) - 3/10 - Having already afforded Vale a free header in one of the few slip ups from Brentford's well-drilled rearguard, Jansson couldn't contort his body out of the way of James' fizzed cross.
Mads Bech Sorensen (CB) - 5/10 - Not content with dislodging Pinnock from his normal left sided slot in the back three, Sorensen took over long throw duties - though represented a downgrade in both roles.
2. Midfielders & wingbacks
Sergi Canos (RWB) - 4/10 - Restricted in his raids forward by the aggressive positioning Chelsea's own wingbacks.
Mathias Jensen (CM) - 4/10 - Skirting around the fringes of the contest, Jensen was wasteful with his set piece opportunities.
Vitaly Janelt (CM) - 7/10 - Made an admirable stab at filling the sizeable shoes of Christian Norgaard at the base of Brentford's midfield before the Dane himself replaced Janelt.
Shandon Baptiste (CM) - 7/10 - So often the driving force on Brentford's sporadic surges forward.
Rico Henry (LWB) - 7/10 - Somehow denied an assist despite creating his team's best chances while on the pitch.
Yoane Wissa (ST) - 3/10 - Shrank out of the fixture after a glaring first half miss.
Bryan Mbeumo (ST) - 6/10 - Haring around with the feverish endeavour that has come to be expected from the Frenchman, he couldn't offer the same positives on the ball.
Ivan Toney (ST) - 5/10
Christian Norgaard (CM) - 5/10
Saman Ghoddos (LWB) - N/A
Frank Onyeka (CM) - N/A
Marcus Forss (ST) - N/A
Chelsea player ratings
5. Goalkeeper & defenders
Kepa Arrizabalaga (GK) - 8/10 - A combination of poor finishing and astute positioning ensured Chelsea's second choice keeper didn't have to heave himself across goal to deny his opponents.
Cesar Azpilicueta (CB) - 7/10 - Increasingly in control of Brentford's attempts to canter forward.
Trevoh Chalobah (CB) - 7/10 - Anchoring Chelsea's back three, the 22-year-old took well to the newfound seniority in a side littered with junior academy graduates.
Malang Sarr (CB) - 5/10 - Tucking alongside Chalobah to make a four as Chelsea built from the back, Sarr was decidedly unconvincing when faced with a challenge in the air.
6. Wing-backs & midfielders
Xavier Simons (RWB) - 4/10 - Chelsea's oldest debutant of the night was easily the shakiest, repeatedly caught out by Brentford's jet-heeled Henry.
Saul Niguez (CM) - 7/10 - Any appearance that bleeds into the second half feels like a win for Saul this season - though this was one of his more impressive outings both on and off the ball.
Mateo Kovacic (CM) - 7/10 - Drifting through the thirds to knit Chelsea's possession wherever the ball went, the normal silk of Kovacic's game was tinged with rust.
Marcos Alonso (LWB) - 6/10 - Had his unshackled first half forays forward reigned in after the interval, which helped the entire side tighten up.
Ross Barkley (RW) - 4/10 - Roaming around in search of the ball, Barkley was more indecision than incision.
Jude Soonsup-Bell (ST) - 6/10 - Linked well outside Brentford's box (particularly with his fellow debutants) but struggled to exert any impact inside the area.
Harvey Vale (LW) - 7/10 - Floating menacingly between the lines, the 18-year-old littered his performance with delicate flicks and spins, impressing most when limited to a sliver of space.
Jorginho (CM) - 6/10 - Immediately matched and then dictated the tempo of contest Chelsea seemed intent to play strictly at walking pace.
Christian Pulisic (ST) - 5/10 - Struggled to cause any notable headaches until his fresh legs helped him nip ahead of Fernandez in the closing stages.
Mason Mount (LW) - N/A
Reece James (RWB) - 7/10 - Left Jansson with little option other than deflecting the ball into his own net such was ferocity of his low cross.
N'Golo Kante (CM) - 7/10 - Played a crucial role in the build up to Chelsea's opener.