The 15-year-old Castle Hill singer is one of eight contestants left in the competition — the last girl standing in the "women under 25" group mentored by former Spice Girl Mel B.

Dubbed as the show's "rock chick", Christina performed an acoustic version of Zombie on October 17.

She played the piano in the dark and let her voice impress during the sombre performance, her first "serious" one in the competition.

Her father Jim Papoulias said he was a bit nervous about her choice to sing The Cranberries' Zombie.

"But she told me 'Dad, you're just old, all the teenagers like it'," he said.

And it seems she was right to follow her instincts with judges Mel B, Ronan Keating, Guy Sebastian and Natalie Bassingthwaighte all giving her a big thumbs up for the performance that saw Christina safe for another week in the competition.

Christina said on the show that being the last of Mel B's proteges meant she had to work a lot harder.

"There is a lot of pressure," she said.

Mr Papoulias said that during one of his daily phone conversations with Christina she had feared she was in the bottom two last week and got a bit emotional.

"But she's in fine spirits now," he said.

"She is grateful for all she's learned so far and she now feels she has a good chance to win the competition.

"She's only 15 and she's one of the two favourites to win. She's done amazingly well and she's totally excited about it. We've been to watch all her shows and she has the support of her huge Greek family and all her school friends."

¦ Catch Christina Parie on The X Factor Australia on Mondays and Tuesdays at 7.30pm on Channel Seven.