Lord Sugar will choose either McCullagh or Brownless as the winner of the show and offer them a £25,000 investment in their future business plans.
Talking to Digital Spy about his strengths in the competition, McCullagh described himself as an ideas man and highlighted that as a weakness in his show rival.
McCullagh said: "Zara is a very worthy finalist and she's an incredible speaker. And she's incredible at pitching as well. However, she does have weaknesses as well.
"Throughout the process she never put forward any ideas. She might have developed a product, but she never created one. For me, business is all about idea. The biggest difference between Zara and myself is ideas. And I think that's what separates a great entrepreneur from a great employee."
McCullagh also took the time to defend fired candidate Harry Maxwell, with whom he had numerous run-ins on the reality show.
"Harry M was definitely one of the most interesting characters that I met on Young Apprentice," he said.
"I don't have a bad word to say about him. He has good ideas and I think he was a really strong candidate. Lord Sugar said that he was unlucky to lose every task. I have to say, I do agree with that in some respects. There was more to Harry M than what we saw and I think he was a great candidate."
Young Apprentice: The Final airs tonight (December 12) at 9pm on BBC One.
> Young Apprentice James McCullagh, Zara Brownless interview