Earlier Chelsea survived an early scare when Crystal Palace had an Eberechi Eze goal controversially disallowed in a scrappy 0-0 draw.
Chelsea, whose last competitive outing was winning the Club World Cup in the US in July, failed to stamp their authority on the game against the FA Cup holders despite more than 70% possession, in warm southwest London sunshine.
Coach Enzo Maresca gave new signings Joao Pedro from Brighton and Jamie Gittens from Borussia Dortmund starts, but neither could make a breakthrough and Chelsea managed only three shots on target out of 19 attempts.
The visitors looked to have taken the lead in the 13th minute but referee Darren England consulted the pitchside monitor and ruled Palace captain Marc Guehi, who shoved Moises Caicedo out of the way, was too close to Chelsea’s defensive wall when Eze took a free kick on the edge of the area.
It was a technical ruling, with the laws of the game stating that where three or more defending team players form a wall, the attackers must be at least one metre from the wall and England spent some time explaining his decision to Guehi.
Nottingham Forest piled more misery on depleted Brentford as new winger Dan Ndoye scored his first goal for the club in a 3-1 win.