On Sunday evening, in his first speech after defying history and pollsters to win the presidency, Luiz Inácio Lula da Silva had a conciliatory message.

“Once we’ve won the election, we have no more opponents. I have to govern for 214 million people,” he said.

Inside his campaign’s watch party, where his political allies and journalists climbed on to chairs for a better view of the Left-wing veteran, and outside on the streets of São Paulo, where supporters waved flags and chanted “Lula”, it was easy to believe in that message of national unity.

But there is also the other Brazil, the one represented by his opponent, Right-wing senator Flávio Bolsonaro, who just under half of the country voted for.

Speaking minutes later, Mr Bolsonaro said: “What happened today was not normal; in fact, it was unacceptable.”He called for the vote to be annulled and claimed, because of a voting extension, Lula’s victory had been the result of “a dirty trick”.

Lula made history in more than one way on Sunday – he is the first-ever candidate to win a run-off after losing the first round of voting since Brazil’s return to democracy. He is also Brazil’s longest-serving democratic leader.

Lula waves at supporters after winning the presidential election Finally, he managed to buck a trend that has seen Right-wing candidates triumph in the region in the last seven general elections.

His victory should have signalled the end of a tumultuous campaign marked by corruption scandals, allegations of US interference and voter suppression, as well as a Harry Potter-inspired social media war.

But it is already clear that will not happen, with deep division and political polarisation spilling over into the country’s institutions.

That much was evident on election day when, in an extraordinary move, Cristiano Zanin, a Supreme Court justice, extended voting by two hours, from 5pm to 7pm, after Lula’s team accused pro-Bolsonaro mayors of voter suppression. Mr Zanin had previously served as Lula’s personal lawyer. Lula’s campaign said officials in some nine states had reduced or otherwise hindered public transportation routes, making it more difficult for voters to get to the polls.

The last time voting was prolonged beyond the formal deadline was in 1994.

Even before voting ended, both camps were framing events on their own terms.

Rogério Marinho, Bolsonaro’s campaign chief, called the extension of voting a “judicial coup”.

Meanwhile, André Janones, Lula’s head of social media, urged supporters that, despite the inevitable triumph that awaited them, “we cannot let this victory make us forget the attempted coup that was perpetrated this afternoon”.

Once it became clear that Lula had won, far-Right politician Renan Santos called it “tainted”.

Mr Bolsonaro called the results ‘unacceptable’ and refused to concede He said the election should be held again “to avoid conflict, including the possibility of armed conflict or street clashes”.

It was a clear reference to the violent clashes that erupted on Jan 8, 2023, when Jair Bolsonaro supporters stormed the Supreme Court, Congress and the presidential palace, a week after Lula took office.

Bolsonaro was sentenced to 27 years in prison for directing a coup, which included a plan to have Lula killed. But if this election cycle has proved one thing, it is that the underlying polarisation that led it hasn’t gone far.

With one day to go until the election, most pollsters could not give a picture on who was in the lead, predicting a margin so thin that even an event as seemingly insignificant as the weather could sway the outcome one way or another.

One read of the choice Brazilians had in the election was that it was one between Right-wing change, represented by Mr Bolsonaro, and Left-wing continuity, represented by Lula. But, on the ground, the campaign had an entirely different flavour.

Supporters flooded streets in Brazil to celebrate Lula’s win In the candidates’ first televised debate, personal attacks over corruption and Banco Master, the biggest banking scandal in Brazil’s history, took up more airtime than policy, forcing the host of the second debate to warn against personal insults. The standoff between the two sides played out as much online as it did on the streets.

A WhatsApp group called “Lula’s army” — a nod to “Dumbledore’s Army”, the group of students who fight evil forces in the Harry Potter series — with more than 10 million followers, was suspended twice after the head of Brazil’s electoral court, a Bolsonaro ally, argued it contained misinformation. Both times, his fellow judges overturned the decision.

Separately, Lula’s team earlier this month filed a complaint with the court accusing Meta of suppressing its content while amplifying Mr Bolsonaro’s. Meta has denied campaign meddling and has called the problems experienced by Lula’s team “technical incidents”.

An aerial view of Lula supporters celebrating the president’s re-election To a large part of the electorate, both candidates represent a rotten political culture, that allows corrupt practices and influence peddling to continue.

Against that backdrop, the candidates’ main capital was to inspire fear towards and rejection of the other.

Mr Bolsonaro campaigned to free his father and impeach the judge that convicted him, Alexandre de Moraes. Lula’s team warned a Bolsonaro win would be the end of democracy and national sovereignty.

The discrediting strategy worked. According to a survey published by the Brazilian pollster Datafolha on the eve of the vote, 44 per cent of respondents said they feared a Bolsonaro victory, compared to 42 per cent that feared another Lula term.

Supporters lit flares and fireworks as they paraded through streets The abstention rate during the first round of voting earlier this month was at its highest since 1998 – one in five Brazilians stayed home.

After losing to Bolsonaro by 2 percentage points, Lula’s campaign set about turning it around, mounting an energised social media push and went on a spending spree.

It gave him new momentum, with pro-Lula groups organising some of the largest political rallies in recent Brazilian history in a groundswell of support. During the run-off on Sunday, the abstention rate was the lowest since 2006, to Lula’s benefit.

“People went to vote because we convinced them it was important to preserve democracy,” Lula said in his victory speech.

But even having won, he was not done with his opponent. “I never imagined that a person could lie so much. As if there wasn’t a shred of humanity in him,” he told the room early on in his victory speech.

Such an attack might have been unwise given that Lula now faces the daunting task of governing with a congress dominated by Bolsonaro’s Liberal Party, the PL.

But in an early sign of how tense the standoff between the executive and legislative is likely to become, Reginaldo Lopes, a PT legislator, told journalists: “Congress is an enemy of the people.”Early on Sunday, Eduardo Leite, the centre-Right governor of Rio Grande do Sul, who dropped out of the presidential race earlier this year, told reporters he had voted for “the lesser of two evils”, without disclosing for whom.

Considering how small the margin was likely to be, he urged the winner to avoid triumphalism in a closely divided country. So far, neither Lula nor Bolsonaro appeared to take his advice.