Sen. Flavio Bolsonaro leads Brazilian President Luiz Inacio Lula da Silva by one percentage point in voting intentions ahead of a presidential runoff, according to a Quaest poll published Wednesday by Brazilian news portal UOL.

The survey showed Bolsonaro with 45% of voter preferences, compared with 44% for Lula, placing the candidates in a technical tie within the poll's margin of error of two percentage points.

The survey was conducted nationwide with 2,154 voters aged 16 and older from Oct. 17 to 20. It was commissioned by TV Globo and registered with Brazil’s Superior Electoral Court.

The results show a slight narrowing of Bolsonaro's lead from the previous Quaest survey on Oct. 14, when he received 46% of voting intentions, with 44% for Lula.

UOL said 9% of respondents said they would cast blank or invalid ballots, or would not vote, while 2% remained undecided.

In a spontaneous voting survey, Lula and Bolsonaro received 40% of responses. An additional 14% of respondents were undecided, while 6% said they would cast blank or invalid ballots or abstain.

The runoff is scheduled for Oct. 25, following the first round on Oct. 4, when Bolsonaro received 47.3% of valid votes, according to official results. Lula secured 45.2%.

Bolsonaro, the son of former President Jair Bolsonaro, is challenging Lula in Sunday's runoff as both candidates seek the presidency.

The region is watching the election closely, given Brazil's economic weight and diplomatic role in Latin America.

The next president will face challenges including economic growth, public security and Brazil’s position on international issues.

Lula is seeking a fourth, non-consecutive term, while Bolsonaro is trying to secure the presidency for his political family after his father's 2022 defeat.