Chelsea lost their fifth successive game since the return of Frank Lampard as Brentford won at Stamford Bridge to strengthen their position in the Premier League’s top 10.
The visitors did not have a shot on target in the first half but took the lead midway through when Mathias Jorgensen’s flick from a corner hit Cesar Azpilicueta on his shoulder to deflect into the back of the net.
Chelsea once again struggled to create chances and a hugely disappointing first half ended with boos from some of the home supporters.
The Blues did improve after the break, thanks largely to the introduction of striker Pierre-Emerick Aubameyang, who mis-hit an overhead kick from a dangerous position before firing a low strike at Brentford goalkeeper David Raya.
But they failed to find an equaliser and Brentford wrapped up a hugely impressive win late on when Bryan Mbeumo cut into the box before smashing a shot into the back of the net.
The defeat leaves Chelsea in the bottom half of the table as they sit 11th, six points behind Fulham in 10th and eight behind Brentford, who move up to ninth.
Miserable campaign can’t end soon enough for Chelsea
This is a season that Chelsea fans will just want to come to an end, with the return of club legend Lampard having failed to steady the ship.
Every game since the 44-year-old’s appointment on 3 April has ended in defeat – three in the Premier League and two in the Champions League – while the Blues have scored just once so far under Lampard’s watch as their season-long struggle in front of goal continued.
Chelsea fans’ hopes of seeing that dismal run ended on Wednesday would not have been lifted by the team news, as Lampard selected what appeared to be a pretty conservative side to try and halt the run of losses, with Joao Felix and Mykhailo Mudryk on the bench and Raheem Sterling leading the attack.
Consequently, they offered almost no attacking threat in the first half, with Thiago Silva’s tame header the best of their few opportunities.
The introduction of Mudryk and Aubameyang at the start of the second half saw a brief improvement in Chelsea’s attacking threat, with the latter providing the Blues with more of a focal point up front.
But they failed to capitalise on that as Brentford punished them with the sort of clinical finishing they crave when Mbeumo scored Brentford’s second with their first shot on target.
While it has long since looked unlikely, this defeat officially ended Chelsea’s chances of a top-four finish as they sit 20 points off fourth with six games remaining.