"The only people I have to prove myself to is the manager of the football club that I'm playing at and my team mates that I'm playing with," the 30-year-old told the BBC.
"I made a few big errors and we all know that... it gets noticed. I'm not stupid... I basically made my own mistakes out of nothing, so as ridiculously as bad as they were, they are also easy to correct."
Cahill's place in the starting line-up is looking increasingly vulnerable after Chelsea signed defender David Luiz in August with captain John Terry and fellow centre back Kurt Zouma also nearing a return from injury.
However, the England international was unconcerned by the raised intensity in the battle for places in the Chelsea defence.
"I am my own fiercest critic, I do look at myself of course. I think that's the way you should be and is the way I have improved. That's how I got to where I am today," he said.
"I don't point (the blame) at everybody else. I look at how I can improve... Whether it's club level or international level, there's always competition. It's good."
Cahill, who is closing in on a 50th cap for England, is part of the national squad for World Cup qualifiers against Malta at Wembley on Saturday and in Slovenia three days later.
(Reporting by Shravanth Vijayakumar in Bengaluru; Editing by John O'Brien)
