That hasn't helped Antonio Conte's chances of remaining at Chelsea after the end of the season.
Defender Cahill, who has won the league twice in six years with the Blues, said Monday's defeat was the club's "lowest point of the season".
"I have a great disappointment, our performance was very bad", Conte said.
"It is very hard for me to transfer my thoughts", Conte told a post-match press conference.
He said: "We just need to keep strong". I've been here before at this club - it's about staying calm.
"It was abysmal. It hurts a lot when you come off after a performance like that".
However, that did little to stem Watford's tide and they went in front when Thibaut Courtois brought down Deulofeu as he rounded the goalkeeper.
"But I still think there's enough experience in the coach and that team to finish in the top four".
"We showed that we wanted to fight even with 10 men and that shows we have character, but when you lose twice like that it is not good and there are questions raised, but we go back to training with the manager, and training well and turn this situation around".
There, they have a tough task of having Spanish side FC Barcelona to take on later this month.
Conte and several of his players have admitted in recent weeks that they are struggling to cope with the demands of a gruelling and, at times, unfavourable schedule that required Chelsea to play nine games in December and nine more in January.
"I just think for eight million a year you want some professionalism, I don't want to see this in public, I want them to get their act together in the board room and sort it out with him".