Results indicate that far-right libertarian outsider Javier Milei has emerged victorious in Argentina's presidential run-off election.
His rival, the centre-left minister of economics and finance Sergio Massa, called Mr Milei to congratulate him.
Also congratulating him was the man who is often compared to the new Argentinian leader, former US president Donald Trump, who declared Mr Milei would "Make Argentina Great Again!".
After more than 90 per cent of the ballots were tallied, Mr Milei received roughly 56 per cent of the vote, while Mr Massa received 44 per cent.
Argentina is going through a tough period due to a crisis-ridden economy and out-of-control inflation, with 40 per cent of the country now living in poverty.
Desperate voters supported Mr Milei's suggestions, which included "blowing up" the central bank.
Provisional data indicate that he surprised pollsters by easily defeating the governing Peronists' candidate by almost 10 points.
But who is the new Argentine president?
Who is Javier Milei?
Mr Milei is an Argentine economist, author, and politician who is the president-elect of Argentina.
He is also a Mick Jagger impersonator known as El Loco (the Madman).Mr Milei identifies as a liberal libertarian, specifically identifying with minarchist and anarcho-capitalist ideals.
He has been described as populist, right-wing libertarian, ultraconservative, far-right, and ultraliberal in politics. His opinions set him apart in the Argentine political scene, and have sparked both political and public responses.
He has proposed the abolition of the Central Bank of Argentina, which would result in a de facto dollarised economy and a comprehensive overhaul of the country's fiscal and structural policies. El Loco also strongly opposes abortion, even in cases of rape.
Mr Milei has also referred to comprehensive sex education as a type of "brainwashing" and opposed it. He believes selling human organs should be legal, is in favour of civilian gun ownership, and has also called the Pope "a lefty son of a bitch".
Federico Finchelstein, an Argentinian historian who studies the global far right, said on the eve of Sunday’s election that he was even more dangerous than Trump, “He is way more excessive and unstable than [Jair] Bolsonaro and Trump. So it’s highly unpredictable what this person could do [in power]."
Before being well-known politically, Mr Milei was an economist. Prior to the October presidential election, the political establishment in the nation was rocked by his triumph in the August primary elections.
He belongs to both the World Economic Forum and the B20, the International Chamber of Commerce's economic policy group. In a prior position, he was the principal economist and financial advisor to businessman Eduardo Eurnekian at a private corporation. He has also been an economics professor, and a talking head on TV, as well as a radio presenter.
Mr Milei, also a music enthusiast and was the lead vocalist for Everest, a Rolling Stones tribute band.
