It was a victory Liam Rosenior's side did not play at their best, but instead were handed down to poor decision making from Keith Andrews' side.
Nonetheless, they will not care as they moved to sixth, just two points off Liverpool in fourth after the Reds were held to a 1-1 draw by Burnley.
For the Bees, they drop to seventh after a six-game unbeaten run in the league.
Cole Palmer (second left) celebrates Chelsea's second goal in their 2-0 win over Brentford. _(Image: PA)_
The Bees started brightly and had the first shot of the game after barely a minute, but Kevin Schade's effort lacked power to trouble Robert Sánchez.
Michael Kayode made an swift run in to the penalty area but his lobbed cross was just behind Igor Thiago, who would have had a free header at goal.
Schade had a glorious opportunity to give Brentford the lead. With Sánchez to beat, the German decided to pass to Mikkel Damsgaard with Tosin Adarabioyo almost diverting in to his own net but Sánchez was alert to spare his teammate the ignominy of an own goal.
However, it would be Chelsea that broke the deadlock through João Pedro. Michael Kayode's clearance riocheted off a Chelsea player, in to the path of Pedro who was initially flagged offside.
However, following a VAR check, the Brazilian was onside and Chelsea went in front despite the visitors having the better of play.
Chelsea's Joao Pedro (second left) celebrates giving the Blues the lead against Brentford. _(Image: PA)_
Brentford did not let their heads drop, with Mathias Jensen hitting the outside of a post.
The Bees started the second-half with the same aggression and intensity than they began and ended the first, and they again came close to an equaliser.
An excellent pass from Jensen played in Schade who was through one-on-one against, but Sánchez denied the German and Brentford an equaliser.
It proved to be a decisive moment in the game as the Blues were handed the opportunity to seal all three points.
A poor pass from Nathan Collins played Caoimhín Kelleher in trouble, with the goalkeeper taking down Liam Delap.
Referee John Brooks pointed to the spot with Cole Palmer sending the Irishman the wrong way to seal Rosenior's first league win in charge.
**Chelsea:** Sánchez; James (Acheampong 85), Chalobah (Fofana 58), Tosin, Cucurella; Caicedo, Fernández (Hato 85); Neto, Palmer, Garnacho (Andrey Santos 57); João Pedro (Delap 74).
**Brentford:** Kelleher; Kayode, Ajer, Collins, Henry (Hickey 82); Janelt, Yarmoliuk (Donovan 90), Jensen; Damsgaard (Ouattara 77), Thiago, Schade (Lewis-Potter 82).