Left-wing challenger Luiz Inacio Lula da Silva’s lead over far-right incumbent Jair Bolsonaro has narrowed slightly on the eve of Brazil’s polarizing presidential election, according to a poll released Saturday night.

According to the Datafolha Institute poll, Lula has 52 percent voter support versus 48 percent for Bolsonaro — up from a six-point gap (53 percent versus 47 percent) last week.

The numbers exclude voters who plan to cast blank or invalid ballots — four percent of respondents, Datafolha estimates. Undecided voters accounted for only two percent.

The margin of error for the poll, which was based on Friday and Saturday interviews with 8,308 people, was plus or minus two percentage points.

According to Datafolha, only half of those surveyed watched an insulting final debate by rivals on Friday night, 19 percent of them to the end.

Lula, the charismatic but ailing ex-president who ruled Brazil from 2003 to 2010, won the first round on Oct. 2 with 48 percent of the vote, versus 43 percent for former army captain Bolsonaro.

Bolsonaro and his allies have attacked polling firms, accusing them of bias.

Already in the first ballot, he exceeded the expectations of the pollsters and afterwards boasted triumphantly: “We beat the lie.”

Lula, who turned 77 on Thursday, leads among women (51 percent), the poor and working class (57 percent) and Catholics (56 percent), according to Datafolha.

Bolsonaro, 67, leads among evangelical Christians (65 percent) and more affluent voters (52 percent).