Almost 15.6 million registered voters in Chile are set to cast ballots on Sunday.
The runoff pits Jose Antonio Kast, from the far-right Republican Party that he founded, against Jeannette Jara, the incumbent leftist government's coalition candidate from the Communist Party.
While Jara won November's first round with 26.85 per cent of the vote, Kast beat an array of right-wing candidates to finish second with 23.92 per cent.
Most of the voters who supported those candidates are projected to go for Kast, which would give him more than 50 per cent of the vote and the presidency.
As the campaigns wound down, both candidates threw jabs at each other, but also focused on the main topic that has come to define the election: crime.
Speaking on Thursday from behind a clear protective barrier in the southern city of Temuco, the capital of a region rattled by conflict between Indigenous Mapuche groups and the government, Kast described a country in chaos and said he would restore order.
"This government caused chaos, this government caused disorder, this government caused insecurity," the 59-year-old lawyer said.
"We're going to do the opposite. We're going to create order, security and trust."
While Chile remains one of the safest countries in Latin America, a recent surge in organised crime and immigration has rattled the electorate and become the main concern among voters.
The issue quickly became a thorn in the side of leftist President Gabriel Boric, who rose to power on a wave of progressive optimism following widespread protests against inequality and promises of drafting a new constitution.
Boric, who is barred from re-election because of a prohibition on consecutive presidential terms, scrambled to adjust, boosting funding for police forces, creating task forces dedicated to fighting organised crime, and deploying the military to the country's northern border with Peru and Bolivia.
But it wasn't enough for many voters.
A Kast victory is likely to be cheered by investors hoping a market-friendly government will accelerate economic reforms, including deregulation and changes to the copper-rich country's pension system and capital markets.
The Chilean peso strengthened and MSCI's Chile equity benchmark surged after the first-round results in November.
Although no clear majority emerged in the Senate or Congress in that vote, Kast is expected to eventually be able to pass some economic reforms if he wins the runoff.
This is his third run for president, and second runoff after losing to Boric in 2021.
Many of Kast's views were seen as too extreme by voters in 2021, but have found a more sympathetic hearing among an electorate craving security and weary of traditional political parties.
This is the first presidential election under a mandatory voting provision with automatic registration for those older than 18 and fines levied on anyone who doesn't vote.
