The Premier League champions fell to successive three-goal defeats in the top flight for the first time since 1995, ramping up the pressure on under-fire manager Antonio Conte.
Conte's job is understood to be hanging by a thread ahead of next Monday's clash with bottom-of-the-table West Bromwich Albion, but Cahill stressed that it is the players who are to blame for the team's poor form.
"Whatever is decided, the players have to take responsibility. The manager has done an absolutely unbelievable job," he is quoted as saying by the Evening Standard.
"This is the worst I've felt for quite a while. Performance-wise, I didn't recognise us or myself. It was abysmal.
"We just need to keep strong. I've been here before at this club - it's about staying calm. It hurts a lot when you come off after a performance like that."
Following next week's match against the Baggies, Chelsea must face Barcelona, Manchester United and Manchester City in succession.