Stretching back to last season, Chelsea have won just one of their last 13 home Premier League games - a 3-0 triumph over newly promoted Luton Town in August.
Chelsea started the brighter of the two sides at Stamford Bridge and hit the post through Noni Madueke but once Brentford weathered the storm, they came out for the second period in higher spirits took all three points thanks to goals from Ethan Pinnock and Bryan Mbuemo.
Chelsea threw away a two-goal lead at home to draw against Arsenal last week but a point was seen as a step in the right direction. This defeat feels like one step forward and two steps back for the Blues.
"I am not happy. The players and the club also aren't," Pochettino told TNT Sports.
"It's a long time that we need to be more consistent here. We feel that we need to chance that dynamic."
"We need to be more nasty in the last third. We need to be more clinical," Pochettino added on BBC Match of the Day.
"It's a very young group who need to improve in this area more than any other."
