On Saturday night viewers saw her perform Christina Aguilera’s Ain’t No Other Man in a Battle Round duel with fellow contestant Janine Dyer.
The episode was pre-recorded and Mia’s success means she has just one more hurdle to overcome before making it on to the live shows.
The Limbury resident said: “It was tough as I find ballads easier, it’s not the sort of song I’d usually sing.
“I’m not used to performing professionally so I was mainly trying to have fun, rather than be wooden and stand still.
Mia and Janine had been fighting to keep their place on coach Ricky Wilson’s team.
It was a close run thing, with Ricky saying the battle was “incredible” and adding “I need help” [on who to pick].
Fellow coach will.i.am branded the pair “amazing”, with Boy George saying it was “hard to call” before tipping Mia to go through.
Paloma Faith added: “They’re both equally matched, both brilliant singers.”
Mia, who had already overcoming the blind auditions stage last month, got the nod and the 28-year-old electrician said it had been an agonising wait while the coaches deliberated her fate.
The former Lea Manor High School pupil said: “It was so much longer than you see on TV. They edit it down. We were waiting quite a while.
“I had made my peace with going home. Janine is very experienced. I was pinching myself for getting through. I was really, really shocked, I wasn’t expecting it.”
In Saturday’s forthcoming Knockout Round the coaches watch each of their eight contestants perform and must choose the best three acts from their team to continue on to the live shows.
On her chances, all Mia would say was: “It’s 32 down to 12 of us, so it’s a massive cull. It is going to be quite a close one again!”.