In the middle of his pilgrimage to Brazil this week, Pope Francis will bless the new altar at a tiny sandstone chapel in a slum on Rio’s northern edge and then address followers at a soccer pitch up the street.

Eager to see the Holy Father in his first major trip, which began with his arrival Monday in Brazil, the crowds here in the Varginha neighborhood will be energized, and the pontiff will undoubtedly win admirers for his man-of-the-people style.

But the religious order in this shantytown will remain the same when he leaves: The chapel is one small Catholic outpost surrounded by a sprinkling of evangelical churches, a microcosm of the challenges the Vatican faces in the world’s most populous Catholic country.

With 200 million people, the vast majority of whom profess some faith, Brazil is a huge battleground for souls. It has one in 10 of all the world’s Catholics, making it enormously important to the Vatican. But for years now, Catholicism has been on the losing end of a pitched struggle with increasingly influential evangelical churches.

Among those contesting the supremacy of Catholicism here in Varginha is the Assembly of God church, where a broad-shouldered pastor with a golden smile, Elenilson Oliveira, jams on an electric guitar and uses his booming voice to urge neighborhood residents to join. Many have.

His services are boisterous and improvised, with would-be pastors invited to the pulpit in the middle of a service to have their say, no matter how rambling their message. The faithful come seeking salvation and help with their daily travails — drug addicts and unwed mothers, old ladies and teens confused about the future. Some simply find joy in the services, in which Oliveira leads seven musicians and singers in rousing Gospel songs.

“What do I like about this? It has to do with me,” said Fernanda Rocha, 21, a receptionist. “It’s festive, animated, it’s for young people. People come here and we sing and we dance, all of this for God.”

In 1960, more than nine out of every 10 Brazilians considered themselves Catholic. Now 42 million say they are evangelical, more than one in five Brazilians. Most of those are Pentecostal, taking part in ceremonies in which the faithful speak in tongues and seek to have demons purged from their bodies.

Animist cults, such as Candomble and Umbanda, also count a high number of adherents. Growing millions say they have no church affiliation or are agnostic or atheist.

The Catholic Church is banking on Pope Francis, 76, an Argentine who brings a Latin American sensibility coupled with charisma and a humble style, to turn the tide back its way. Upon his arrival Monday, the Holy Father immediately showed his populist side, waving from a small car chugging through Rio’s traffic-choked streets, touching those who reached inside and kissing a baby that was handed to him. “I don’t have gold or silver — I bring the most precious thing given to me, Jesus Christ,” the pontiff said in a 10-minute speech at the governor’s palace, with Brazilian President Dilma Rousseff at his side.

The pope’s simple, folksy style and advocacy for the poor have already brought him closer to people, religious analysts said.

“With him there is more space to reach people,” said Paulo Fernando Carneiro de Andrade, dean of the theology center at the Catholic University in Rio. “He has empathy in the way he talks to people. It’s an evangelical way. And that’s very important. People are very enthusiastic. That helps a lot.”

Francis faces a wealthy and politically influential evangelical movement. It includes a range of showman preachers who oversee institutions with millions of members, such as Edir Macedo of the Universal Church of the Kingdom of God, a billionaire who controls the country’s second-largest TV network.

Evangelicals have a growing presence in a range of political parties and hold nearly 70 seats in the 513-seat lower house of the Brazilian legislature. Their numbers and ability to work together make them a force to contend with on such issues as gay rights and the legalization of abortion, both of which they sharply oppose.

“Gay activism is moral garbage,” one influential minister, Silas Malafaia, told 40,000 followers outside Brazil’s National Congress recently, according to the Reuters news agency. “Satan will not destroy our family values.”

But such political issues seem less important to many evangelicals than the energy and warmth of their church communities and the chance to participate in religious services in ways that are unusual in traditional Catholic Masses. Then there is the draw of charismatic preachers.

On a recent night at the International Evangelical Community in Rio’s fashionable Flamengo neighborhood, popular singer Sara Alencar belted out one song after another in a low, silky voice. With the crowd warmed up, the Rev. Marco Antonio Peixoto hit the stage, his image projected on a huge screen as hundreds clapped and waved their arms.

Peixoto energetically moved around the stage, microphone in hand, and pledged that God “will get you a solution” to life’s quandaries. “Your problem is not meant to destroy you but to improve you — you are meant to overcome!” he said. “Keep your eyes open because his blessing might be right in front of your eyes.”

Not far from Flamengo, at the Seventh Day Adventist Church, a well-dressed crowd listened intently as Gisleide Novelo, 31, spoke of how her baby, Pietro, got better after an emergency blood transfusion. Prayers from fellow congregants, she said, helped him survive. “He was always a baby of the church,” she explained.

For the pastor, the Rev. Willians Avellar do Carmo, a former Catholic, his church thrives because congregants can let their voices be heard — whether they are telling their stories of faith, as Novelo did, or singing or taking to the pulpit.

“We give attention that’s more personalized,” Carmo said

Ana Maria Prado Barbosa, 66, a lawyer and former Catholic, said she felt little connection to her former church’s services, in which she said “the father starts a homily where he talks to no one.”

“Here there is a language of God you can understand,” she said.