Brentford stunned Chelsea with three unanswered second-half goals to claim a commanding 3-0 Premier League victory at the Gtech Community Stadium.
After a tight opening 45 minutes ended goalless, the hosts transformed the contest after the break, with Jaidon Anthony opening the scoring before Igor Thiago and Fabio Carvalho completed an emphatic West London triumph.
Chelsea had enjoyed spells of control during the first half but struggled to turn possession into clear chances. Pedro Neto forced Caoimhin Kelleher into an early save after Danny Welbeck brought the ball down inside the area, while Morgan Rogers failed to make the most of the rebound.
Brentford's best opening before the interval came through Yehor Yarmoliuk, whose low drive was comfortably dealt with by Emiliano Martinez. The sides went into the break at 0-0 after a cagey first half in which neither attack consistently found a way through.
The breakthrough arrived in the 61st minute from a set piece. Mikkel Damsgaard's corner reached Jannik Schuster, who headed the ball back into the danger area for Anthony to convert from close range and put Brentford ahead.
Chelsea attempted to respond and enjoyed a dangerous spell around the Brentford penalty area. The visitors appealed for a penalty in the 77th minute after Mamadou Sangare caught Valentin Barco inside the box, but a VAR check did not result in a spot kick.
Brentford then delivered the decisive blow with seven minutes of normal time remaining.
Kevin Schade broke forward and forced Martinez into a save, but the rebound fell kindly for Thiago, who finished with his right foot to make it 2-0 and score his first Premier League goal of the season.
There was still time for Brentford to add a third.
Deep into stoppage time, Schade was again involved as his low delivery reached the back post, where substitute Carvalho converted in the 94th minute to complete the 3-0 scoreline.
The final score reflected Brentford's increasingly dominant second-half performance. The hosts finished with an expected-goals figure of 2.65 compared with Chelsea's 0.82, underlining the difference in the quality of the chances created as the game developed.
For Chelsea, the defeat continued a difficult run away from home and exposed their inability to convert periods of possession into goals. Brentford, meanwhile, were rewarded for remaining disciplined through the first half before becoming far more aggressive and clinical after the interval.
Anthony's opener changed the direction of the contest, Thiago gave Brentford breathing room and Carvalho's late finish provided the final flourish on a memorable night for the Bees.