Brentford held on for their third Premier League win of the season as goals from Ethan Pinnock and Bryan Mbeumo sank a wasteful Chelsea in the west London derby at Stamford Bridge.
The Blues, who had 17 shots to Brentford’s seven, were punished through Pinnock’s thumping header from Mbeumo’s wicked cross.
With Chelsea goalkeeper Robert Sanchez up the field for a late corner, Neal Maupay led a Brentford counter-attack and set up Mbeumo for the second.
Chelsea, who went closest in the first half when Noni Madueke struck the woodwork, slipped to a ninth home defeat this year thanks to some poor finishing.
Brentford keeper Mark Flekken was never truly stretched and the visitors defended resolutely before hitting Chelsea on the break.
Victory lifted Brentford to 10th in the table, one point and one place above Chelsea.
Brentford have won on all three of their visits to Stamford Bridge as a Premier League club, and, although Chelsea were largely the better side, Brentford still created their fair share of chances.
Mathias Jensen was given room down the right just after half-time, cutting the ball back to Vitaly Janelt, who guided his shot straight at Sanchez.
Brentford’s goal was also created down the right when Mbeumo fired in a brilliant, pacy delivery and Pinnock sprinted to meet it with a powerful header.
On the break Yegor Yarmolyuk was clean through when he was kept out by Sanchez, before Mbeumo stabbed a shot narrowly wide.
Thomas Frank’s side added a second when Mbeumo tapped the ball into an empty net with only Sanchez nearby.
After a slow start to the season Brentford have now won two games in succession while extending their unbeaten run in London derbies to 13 matches.
Chelsea have yet to find their groove under Mauricio Pochettino.
Against Brentford – a side often praised for their organisation and defensive rigidity – they initially cut through at will, with Madueke curling an effort against the post in the first 10 minutes.
Cole Palmer looked impressive and crossed for an unmarked Marc Cucurella midway through the first half, but his first-time shot was straight at Flekken.
After the restart Chelsea’s wastefulness became more apparent and they did not have a shot on target in the second half.
Since February Chelsea have won only two home league matches – against relegated Leeds last season and newly promoted Luton this term – and have failed to score in four of their 10 games this season.
Chelsea host on Blackburn in the Carabao Cup on Wednesday and Brentford entertain West Ham in the Premier League next Saturday.