Chelsea manager Thomas Tuchel blamed fatigue for an alarming slump in form that continued with a 1-1 draw at Brighton on Tuesday.
The European champions have won just one of their last seven Premier League games to realistically end their title challenge and leave the third-placed Blues looking over their shoulder at the contenders for a top-four finish.
For the second meeting with the Seagulls in 20 days, Chelsea surrendered the lead.
The visitors went ahead through Hakim Ziyech’s snap shot which caught Robert Sanchez in the Brighton goal by surprise.