Brazil’s president Luiz Inácio Lula da Silva has won an unprecedented fourth term – a stunning comeback victory in the face of attempts by far-right opponents to interfere in the election. Lula secured 51.79% of the vote in the run-off on Sunday, 4.4 million more votes than his US-backed rival Flávio Bolsonaro, who secured 48.21%. The leftwing incumbent was the runner up in the first round of voting on 4 October, and polling showed both candidates were neck and neck ahead of the run-off on Sunday. It is the first time since Brazil’s dictatorship ended in the 1980s that a presidential candidate has won an election without coming first in the initial round of voting. “This election was a defeat for denialism,” Lula told a jubilant crowd of supporters in São Paulo on Sunday evening. “I want to thank God and to thank you, Brazilian men and women of this country… it was democracy that made this happen.” Bolsonaro has refused to concede and is calling for Lula’s victory to be annulled. His father, ex-president Jair Bolsonaro, is serving a 27-year sentence under house arrest for attempting to stage a military coup after losing to Lula in 2022. This year’s election was marred by widespread reports of foreign and domestic interference aimed at swaying the vote against Lula. Bolsonaro’s supporters were accused of attempting to prevent people from voting for Lula on Sunday after public transport was shut down in several cities. The issue led Brazil's supreme court to extend voting by two hours to give people more time to reach polling stations. The US was also accused of meddling in the election, including via president Donald Trump’s imposition of tariffs earlier this year, which was seen as an attempt to hurt Lula’s chances. And Lula’s supporters have expressed intense anger at Meta after Lula’s campaign said the company was suppressing his posts on its platforms. Numerous world leaders and other prominent figures congratulated Lula on his victory. “Long live democracy, the people of Brazil won,” Mexico’s president, Claudia Sheinbaum, wrote on X. Former US presidential candidate Bernie Sanders said Lula’s comeback was “extraordinary”. He wrote: “Lula has stood up for Brazilian workers and democracy – and will continue to do so in the next four years.” The election has also been hailed as a victory in the fight against climate chaos. Bolsonaro was expected to follow in the footsteps of his father and rapidly accelerate the destruction of the Amazon rainforest, a vital global carbon sink. Since Lula’s 2022 victory, forest clearing in the Amazon has fallen to its lowest level on record, from 45,600 sq km under Bolsonaro to 24,600 sq km, data from the country’s space agency shows.