Thomas Tuchel said Chelsea's players are "tired mentally and physically" after their 1-1 draw at Brighton left them with just one win in seven Premier League games and 12 points adrift of leaders Manchester City.
The Blues led against the run of play at the Amex Stadium through Hakim Ziyech's low drive, but failed to hold on, conceding a second-half header to Adam Webster from a corner.
They have now taken just three league points from a possible 12 in a 21-day period that has seen them play seven matches in all competitions.
While they continue to fight on other fronts - including the Carabao Cup, in which they qualified for the final last week - their attempts to keep pace with an imperious City look forlorn.