Brentford snatched a 2-0 win away at Chelsea on Saturday as the expensively assembled Blues failed to turn possession into goals once again and were punished by a thumping header from defender Ethan Pinnock and a last-minute breakaway goal by Bryan Mbeumo.
The west London derby defeat was yet another setback for Chelsea coach Mauricio Pochettino, whose side had shown signs of putting a poor start to the season behind them recently with two wins out of three and a 2-2 draw against Arsenal last weekend.
“The frustration is so massive,” Pochettino told talkSPORT radio, saying a strong first-half performance gave way to a lack of calm after the break.
“We are doing our job, we are happy here,” the Argentine said. “We need to be clinical and score more goals. This is what is missing… We need to keep believing.”
Chelsea have now won only one of their last 13 home league games, a dismal run stretching back into last season when they fired managers Thomas Tuchel and then Graham Potter.
Brentford’s third league win at Stamford Bridge in as many seasons meant that they leap-frogged their neighbours into 10th spot, while Chelsea dropped to 11th ahead of the rest of the weekend’s fixtures.