Who is contesting the run-off?
Incumbent President Luiz Inácio Lula da Silva and Senator Flávio Bolsonaro.
What were the reported vote shares?
With 99% counted, retrieved background material reported 47.03% for Bolsonaro and 45.16% for Lula.
Why might Lula have lost support?
Analysts cited economic pressures and a possible shift towards market-oriented politics; these explanations are not confirmed causes.
What else was being elected?
Governors, state legislators, all 513 federal lower-house members and 54 senators.
Who is running in the run-off?
Flávio Bolsonaro and incumbent Luiz Inácio Lula da Silva.
What were their reported first-round shares?
Bolsonaro had 47.03% and Lula 45.16% with 99% counted, according to the BBC.
Why is there a run-off?
Neither candidate received more than 50% of the vote.
Who is Flávio Bolsonaro?
He is the son of former president Jair Bolsonaro.
What issues featured in the campaign?
The BBC described sovereignty, crime, the economy and corruption as campaign issues.
Who will contest the run-off?
Flávio Bolsonaro and Luiz Inácio Lula da Silva.
Who led the reported first-round count?
Bolsonaro, with about 47 per cent of valid votes to Lula’s 44.9 per cent, with nearly 99 per cent reported.
What other elections are taking place?
Voters are choosing lawmakers, senators and governors.
Are the vote totals and congressional outcomes final?
The source gives reported vote figures and projected congressional gains, not final certified totals.