Cahill said the Blues' squad had as much confidence in their manager now as when he masterminded their march to Champions League glory exactly six months ago.
He said: "From last year, when he took the job, he did tremendously well and achieved such a lot in a short space of time.
"We started the campaign really well.
"We're all behind him and he's definitely the right man.
"He proved it last year and I'm sure he will prove it this year as well."