Just a matter of months after comfortably securing the Premier League crown, the Blues now sit 16th in the standings after Southampton last weekend inflicted their fourth league defeat of the campaign.
It has naturally led pressure to ratchet up on Chelsea's Portuguese manager - talk the club attempted to extinguish by surprisingly releasing a statement saying Mourinho retained their "full support".
It is a move centre-back Cahill certainly supports, highlighting the success and calibre of the man at the Stamford Bridge helm.
"(The statement) is important," he said
"I think everybody knows the situation we're in at the moment.
"It has been a very, very difficult start
The Southampton game, for me personally, was a real low and I've come away here totally determined to make that right when I come back.
"That's the kind of attitude I've got towards it all and I am sure my other team-mates are probably feeling the same - pure determination to turn it around and make sure that when we have the good times again, they're even sweeter because of what we've been through
I think that's important.
"I think in terms of backing the manager, of course we all back him, of course we are all around him.
"Dare I say, he doesn't even need backing
When you've done so much in the game, got the CV and been through everything that he has been, not just in this league or what he has done for Chelsea but in other leagues.
"I don't even think he needs backing, but obviously it is nice to have that and he has certainly got that from the players and the club."
Before Cahill can help Mourinho and Chelsea get back to winning ways comes the small matter of representing England.
Roy Hodgson's men round off Euro 2016 qualifying with a trip to Lithuania after Estonia visit Wembley on Friday, when the Chelsea defender will lead his country out as captain for the very first time.
"Obviously it is an extremely proud moment for me tomorrow, not just for myself but my family," Cahill said, skippering the side in the absence of Wayne Rooney
"It is one I am looking to enjoy as much as I possibly can.
"It is a great honour, a dream come true
Since the boss gave me the vice-captain role I've enjoyed that, but waiting and hoping obviously to at some stage lead the team out.
"I know I've had the armband once or twice when Wayne has come off the pitch, but to lead the team out will be something incredible for myself.
"Definitely a career high for me and something I'm really looking forward to."
Source : PA