Incumbent Ricardo Nunes and leftist lawmaker Guilherme Boulos will face each other in a runoff to decide the next mayor of Sao Paulo, following a first round of voting Sunday in Brazil’s local elections.

A combination picture shows Sao Paulo's mayoral candidates leftist Guilherme Boulos, left, and center-right incumbent mayor Ricardo Nunes react after voting at their polling stations during the municipal elections in Sao Paulo, Brazil October 6, 2024.

An insurgent candidate is splitting the Brazilian right ahead of Sunday municipal elections, testing Jair Bolsonaro’s grip on the rabid movement he has sought to lead even after losing the presidency two years ago.