The right-wing, self-described “anarcho capitalist” Javier Milei has been elected into power in Argentina.
With 99.4% of votes tallied in the presidential runoff after the election on Sunday, Mr Milei had 55.7 per cent and Economy Minister Sergio Massa 44.3 per cent, according to Argentina's electoral authority.
This is the highest percentage that a presidential candidate has received since the South American country's return to democracy in 1983.
The 53-year-old economist, who has been compared to former US President Donald Trump, delivered his victory speech, saying the "reconstruction of Argentina begins today."
He went on: "Argentina's situation is critical. The changes our country needs are drastic. There is no room for gradualism, no room for lukewarm measures.”
Supporters chanted "Liberty, liberty!" and "Let them all leave" in a reference to the country's political class.
Mr Trump congratulated Mr Milei on his platform, Truth Social, when he said: "The whole world was watching! I am very proud of you.
"You will turn your Country around and truly Make Argentina Great Again!"
Mr Massa of the ruling Peronist party had already conceded defeat, saying Argentines "chose another path."
"Starting tomorrow ... guaranteeing the political, social and economic functions is the responsibility of the new president. I hope he does," Mr Massa said.
With a Mr Milei victory, the country will take an abrupt shift rightward and a freshman lawmaker who got his start as a television talking head blasting what he called the "political caste" will assume the presidency.
Inflation has soared above 140 per cent and poverty has worsened while Mr Massa has held his post.
Mr Milei has said he would slash the size of the government, dollarize the economy and eliminate the Central Bank as a way to tackle galloping inflation that he blames on successive governments printing money indiscriminately in order to fund public spending.
He also espouses several conservative social policies, including an opposition to sex education in schools and abortion, which Argentina's Congress legalised in 2020.
"This is a triumph that is less due to Milei and his peculiarities and particularities and more to the demand for change," said Lucas Romero, the head of Synopsis, a local political consulting firm. "What is being expressed at the polls is the weariness, the fatigue, the protest vote of the majority of Argentines."
Mr Massa's campaign cautioned Argentines that his libertarian opponent's plan to eliminate key ministries and otherwise sharply curtail the state would threaten public services, including health and education, and welfare programs many rely on. Mr Massa also drew attention to his opponent's often aggressive rhetoric and openly questioned his mental acuity; ahead of the first round, Mr Milei sometimes carried a revving chainsaw at rallies.
The CEO of Brazil-based pollster Atlas Intel, Andrei Roman, said: "There were a lot of voters that weren't convinced to vote Milei, who would vote null or blank. But come the day of the vote, they voted for Milei because they're all P***ed off.
"Everyone talked about the fear of Milei winning. I think this was a fear of Massa winning and the economy continuing the way it is, inflation and all that."
Mr Milei accused Mr Massa and his allies of running a "campaign of fear" and he walked back some of his most controversial proposals, such as loosening gun control. In his final campaign ad, Mr Milei looks at the camera and assures voters he has no plans to privatise education or health care.
Mr Milei's screeds resonated widely with Argentines angered by their struggle to make ends meet, particularly young men.
A 20-year-old law student, Luca Rodrïguez, said: "Incredibly happy, ecstatic, it's a global historical phenomenon!
"I want to break free from this ridiculous elite that takes away all our rights, all the tax money that pressures us and doesn't let us live in peace."
Some of Mr Milei's positions appear to echo more conservative Republicans in the US while his fiery, profanity-laden rhetoric has already lifted him to prominence in the global culture war that at times overwhelms political discourse in the US, neighbouring Brazil and elsewhere.
Mr Milei opposes feminist policies and abortion, which Argentina legalised in recent years, and has proposed a plebiscite to repeal the law.
He also rejects the notion humans have a role in causing climate change. In a television appearance, he denounced Pope Francis, who is Argentine, as an "imbecile" for defending social justice and called the head of the Roman Catholic Church "the representative of malignance on Earth."
In the same vein as Trump's slogan, "Make America Great Again," Mr Milei has said he will return the country to an unspecified period of greatness.
"Argentina is going to reclaim the place in the world that it should never have lost," Mr Milei said at his victory rally Sunday. His followers have embraced the comparison, and often wear hats bearing the words "Make Argentina Great Again."