Watch: How Brazil's dramatic election unfolded

Brazil’s presidential election is officially heading toward a decisive second round after millions of citizens cast their ballots on Sunday in the opening stage of the national contest, according to a report from BBC News.

The outcome sets up a high-stakes runoff between the incumbent leader, President Luiz Inácio Lula da Silva, and conservative challenger Flávio Bolsonaro. With neither candidate securing an outright majority in the initial voting, the two political rivals are scheduled to face each other in a final runoff vote on October 25.

At 80 years old, Lula is campaigning to secure what would be his fourth non-consecutive tenure leading Latin America’s most populous country. Over his decades-long political career, the veteran leftist has remained a central figure in Brazilian national governance, having returned to office following previous presidential terms.

Standing against him is the 45-year-old right-wing politician Flávio Bolsonaro, who is making his first bid for the nation's highest office. He enters the political spotlight carrying significant family name recognition as the son of former President Jair Bolsonaro, who directed the nation's administration from 2019 through 2022.

The upcoming October 25 ballot brings a direct clash between two established and opposing political movements in Brazil. As the campaign transitions into its final weeks, both camps must now concentrate on expanding their support bases and mobilizing voters across the country to secure victory in the deciding round.