Brazil entered the final stretch of a deeply polarized presidential race Monday after an inconclusive first voting round put far-right incumbent Jair Bolsonaro in an unexpectedly strong position.

Bolsonaro, 67, garnered 43 percent of Sunday's first-round votes compared to 48 percent for leftist frontrunner Luiz Inacio Lula da Silva -- a five-point difference that polls had predicted would be a much larger gap of 14 points.

Ex-president Lula, 76, had appeared to be within arm's reach of taking the election in the first round with more than 50 percent of the vote -- but the race now heads to a October 30 runoff.

Not only Bolsonaro surpassed expectations: many allies of his "God, country and family" brand of conservative politics also performed better than poll predictions in congressional and gubernatorial races.

It signaled enthusiasm for the far-right leader and his policies despite Bolsonaro's controversial four-year tenure, marked by a shocking pandemic death toll blamed in part on his Covid-skeptic approach, surging destruction of the Amazon rainforest, and a sharp rise in Brazilians living in hunger.

The Sao Paulo Stock Exchange welcomed the first-round results in Latin America's largest economy with a rise of more than four percent Monday morning.

'The fight continues'

Both men declared themselves ready for the final campaign to attract the vote of some nine million Brazilians who cast their ballot for minority candidates -- none of whom managed to break through five percent of support -- and 31 million others who did not vote at all.

Lula, who wasted no time convening his campaign team for a strategy meeting on Monday, said: "We will have to convince Brazilian society of what we are proposing."

Addressing dumbstruck supporters in Sao Paulo Sunday, the leftist icon said he would start campaigning without delay, with more meetings with voters.

Lula said he looked forward to debating Bolsonaro head-to-head "to see if he's going to keep telling lies," and promised supporters: "The fight continues until the final victory!"

For his part, Bolsonaro tweeted: "we had more votes in the first round than in 2018 (when he won the presidency) -- nearly two million."

He added: "By the grace of God I have never lost an election and I know that we will not lose this time."

Analysts say Bolsonaro's performance bodes for a stressful and divisive four weeks before the vote.

The incumbent has repeatedly sought to cast doubt on Brazil's electronic voting system and questioned the validity of opinion polls placing him a distant second.

Now, he can argue that Sunday's results bear out his claims.

'Emboldened'

Bolsonaro's rhetoric has raised fears he could trigger a Brazilian version of the riots last year at the US Capitol after former president Donald Trump refused to accept his election defeat.

Bolsonaro "will be very emboldened," by Sunday's electoral performance, said Michael Shifter of the Inter-American Dialogue think tank.

"He's beaten the expectations... He will play on that the experts were wrong: 'I've got the momentum and I'll defy expectations again in the second round'."

Passions will be high on both sides.

Bolsonaro now has "an extra month to cause turmoil in the streets," political scientist Guilherme Casaroes of the Getulio Vargas Foundation's (FGV) Sao Paulo School of Business Administration told AFP.

"Any kind of doubt that he casts upon the electoral system will work in his favor... demobilizing voters not to go vote for Lula" -- who left office after two terms in 2010 with an unprecedented 87-percent approval rating and is credited with helping lift 30 million people out of poverty.

Bolsonaro will continue hammering on Lula's flaws, including his conviction for corruption -- since overturned in court, but not in the court of public opinion, analysts say.

"Lula's chances of being elected seem considerably slighter," said Casaroes.

As for Bolsonaro, it now appeared he "could make this a contest," said Shifter.

"Instead of the great comeback (for Lula) it could be the great upset."

Voter Mateus Alcantara, a 26-year-old publicist, said in Rio de Janeiro his country was living a moment of "enormous polarization"

"Bolsonarism is growing more and more, and this is a reflection of a very conservative country," he told AFP.