SAO PAULO (AP) — The mayor of the largest city in the Americas appeared headed to successfully fending off a reelection challenge from the socialist leader of a squatters movement as 57 Brazilian cities held runoff elections Sunday.

With nearly two-thirds of ballots counted in Sao Paulo, Mayor Bruno Covas had just under 60% of the votes to 40% for Guilherme Boulos, who had been backed by former President Luiz Inácio Lula da Silva.

Covas, the grandson of a former state governor, is a close ally of current Sao Paulo state Gov. João Doria, his predecessor as mayor, and a strong showing might boost Doria's presidential aspirations for the center-right Social Democracy Party.

He campaigned on his performance leading the city of 12 million people through the coronavirus crisis, helping set up field hospitals and pushing for restrictions on activity while challenging President Jair Bolsonaro's dismissal of the pandemic's seriousness. A cancer survivor, Covas also recovered from a bout with the virus in June.

Boulos, the son of university professors, decided at age 16 to become a community organizer in poor areas of the city and hasn't left since, still living in a poor neighborhood with his wife and two daughters. Even with a defeat, he is expected to become one of the most important leftist leaders in Brazil after propelling himself into the mayoral runoff.

One of the leaders of the Homeless Workers Movement, he became known for organizing invasions of empty buildings in downtown Sao Paulo, arguing they should be shared by homeless families.

He recently announced that he had tested positive for the new coronavirus. Unable to vote while quarantining, he appeared on a balcony of his house Sunday to greet supporters.

The emergence of Boulos, of the Socialism and Liberty Party, raised hopes in Brazil’s battered left, long led by da Silva, and he drew energetic crowds to his rallies.

“I wanted to vote for a woman and there weren’t any with a decent shot. I will vote for Boulos because he excites people my age," said telemarketing operator Yasmin Menezes, 23. “I don’t have a problem with Mayor Covas, he is decent, but I think Boulos sends a stronger message against sexists and racists.”

Both mayoral candidates oppose Bolsonaro, whose favored candidate in the mayoral race finished fourth in first-round voting two weeks ago, with half as many votes as Boulos.

Alberto Bueno, a partner at the consulting firm Concordia, said the socialist candidate might become an important leader even in defeat.

“Boulos managed to win over a young audience and energized leftist anti-Bolsonaro voters," Bueno said, adding, "It will depend on his political skill to project his leadership beyond Sao Paulo.”

The conservative Bolsonaro campaigned for some candidates during his live broadcasts on social media in recent weeks, but few of them won.

The president’s biggest setback, other than Sao Paulo, is coming in his hometown of Rio de Janeiro, where his favored candidate, Mayor Marcelo Crivella, was losing by a wide margin to former Mayor Eduardo Paes. With just under 60% of the vote counted, Paes led Crivella by 64%-36%.