Chelsea extended their unbeaten run to seven games under Graham Potter after a goalless draw against a battling Brentford side.
In a hard-fought west London derby, the hosts had three good chances, but Blues goalkeeper Kepa Arrizabalaga twice kept out headers from Ivan Toney and another one from Bryan Mbeumo.
Chelsea saw Cesar Azpilicueta and Kai Havertz both denied by Brentford's David Raya.
Substitutes Pierre-Emerick Aubameyang and Christian Pulisic nearly won it late on for the visitors, but Raya again did well to make vital saves to keep it level.
The point keeps Potter's side fourth, seven points behind leaders Arsenal, while ninth-placed Brentford have now drawn five of 11 Premier League matches this season.