Just 16, Antonio has been one of this year's stars on the Brazilian version of the television talent show.
Her song? Michael Jackson's peace loving "Heal the World."
Although she was finally eliminated on Tuesday, Antonio has left a mark on audiences -- and helped bring hope into her own turbulent life.
"It was very important for me to take part in this program, not just for me but for other children who are refugees. I hope I can be an example and bring a message of hope in the middle of the suffering," she told AFP.
Two years after fleeing the Democratic Republic of Congo, Antonio is still getting used to the dramatic change in her life.
She lives in Sao Paulo, but after her final visit to the TV Globo studios in Rio de Janeiro for the contest this week, she went to see the ocean for the first time.
The happy smile on her face as she strolled along Ipanema beach was also because of the reaction from passersby.
"Bravo, you sing brilliantly and you're a winner whatever happens," said one fan in the street, 26-year-old Rafael, who sells ice.
Every few steps she was stopped by somebody asking to take a selfie with her.
Lost and hiding
In 2015, violence in the DRC capital Kinshasa forced her family to flee. But an attempt to set up a meeting place in case they got separated failed, leaving Antonio and her sister alone and scared.
"I had to run away with my little sister and we lost our mother. We spent three days hiding in the bush," she recalled, nervously touching her long braided hair as she talked.
They were eventually rescued by Brazilian missionaries who brought them to Angola and from there to Rio de Janeiro, even if this meant new heartache.
"I didn't want to leave because I wanted to find my mother again. But I accepted in the end because otherwise I risked dying," she said.
In Brazil, the two girls had an extraordinary surprise when they registered with the Catholic charity organization Caritas: their mother and four other siblings had made the same journey to Sao Paulo just a few weeks earlier.
At the end of 2015, their father arrived too, completing the reunion.
Voice for the voiceless
In Sao Paulo, Antonio discovered her talent for singing when she joined a choir called Somos Iguais, Portuguese for We are the Same.
The choir is a project run by Daniela Guimaraes, originally just to give children something to do while their mothers were educated in breast cancer awareness.
"They sang so well that I felt I had to go further," Guimaraes said.
With help from well known orchestra director Joao Carlos Martins, the choir -- helping children from Angola, DRC, Haiti and Syria -- began performing in several cities. Five members were then invited to audition for Globo's "The Voice Kids."
Antonio was picked, but since she was 16 she was invited to come back and do the adult version of the show instead. On the big stage, she did well enough to get right through to the last rounds.
"Isabel represents the voices of all the other children in our choir and she has been able to use this opportunity to fulfill all their dreams," Guimares said.
"When I sing, I have the impression of being someone else," Antonio said during her trip to Rio. "I am no longer little Isabel who was suffering and afraid of dying."