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.
Bees boss Thomas Frank later said: "The feeling is a strange one as we were playing against Chelsea.
"That day when we got promoted, they won the Champions League final so the difference between the two teams is immense.
"But the performance we had, especially in the first half, we were by far the better team. Overall we should deserve the win, from the 84th minute we were looking a bit tired but I think we did fantastically.
"Kepa [Arrizabalaga] was fantastic. Every time Chelsea come here, their goalkeeper is man of the match. Now we need to recover and I need to find a good starting 11.
"We're going to Villa Park, a really difficult place to go, but we believe we can win."