Former investment banker Pedro Pablo Kuczynski was on track to become Peru's next president after a near-final vote tally gave him a slim lead in the tightest election in decades, although his populist rival Keiko Fujimori had yet to accept defeat.
Outgoing president Ollanta Humala and the leaders of Colombia, Chile, Argentina and Mexico congratulated Mr Kuczynski after the latest official results on Thursday made it nearly impossible for Ms Fujimori to catch up even though Mr Kuczynski led by only 40,000 votes.
Mr Kuczynski, a centrist economist known in Peru by his initials PPK, said he would wait for a complete count before claiming victory as thousands of disputed or unclear ballots remained uncounted.
Mr Kuczynski promised to unify Peru after the divisive election that many saw as a referendum on the controversial legacy of Ms Fujimori's father, imprisoned former authoritarian leader Alberto Fujimori, in Peru's fourth straight democratic election.
“We’re going to work for all Peruvians,” Mr Kuczynski (77) said in a news conference as supporters cheered him in the streets. “We take this virtual verdict with much modesty.”
The thin margin of victory and lack of allies in congress would leave Mr Kuczynski with one of the weakest mandates of any recent Peruvian president.
Either of the two business friendly candidates would face tough economic challenges, as slumping mineral prices have hit Peru, a global supplier of copper, zinc and gold.
To kickstart the economy, Mr Kuczynski has proposed widening the fiscal deficit, lowering sales taxes, and investing in new infrastructure projects.
The latest count put him ahead of 41-year-old Ms Fujimori by just a quarter percentage point, according to electoral office ONPE.
While the gap has fluctuated somewhat in recent days, Ms Fujimori has trailed throughout the vote count.
Still, 0.2 per cent of votes had not be tallied because they were unclear or dispute.
Members of Ms Fujimori’s Popular Force party said electoral authorities should annul bundles of ballots because they had detected irregularities at polling stations.
"Nobody, absolutely nobody. . . can claim victory yet," congressman Pedro Spadaro told reporters.
Some 140 bundles of ballots were still under review by authorities late on Thursday. However, with each bundle holding up to 300 votes, Ms Fujimori would not be able catch up to Kuczynski even if all were in her favour.
Ms Fujimori remained largely silent amid growing calls for her to congratulate Kuczynski.
"Acknowledging defeat would be best for democracy," said Fernando Tuesta, a political analyst and the former head of Peru's electoral board.
Ms Fujimori, who became her father’s first lady at 19 when he divorced her mother, had long been the favourite to win the election, thanks in part to the popularity of the family name in provinces where his government built schools and cracked down on the bloody Shining Path insurgency.
Alberto Fujimori is now serving a 25-year sentence for graft and human rights abuses committed during his 1990-2000 government.
On the campaign trail, she tried to distance herself from her father and criticized him for ordering the military to shutter congress in 1992. But she never acknowledged he committed any crimes.
"I voted for PPK because he is a man with experience and does not have her past," said Mario Palomino (70).
But the broad support that Mr Kuczynski enjoyed as many rallied behind him in the second-round race to defeat Ms Fujimori might evaporate once he assumes power, making it hard for him to govern. His party will control just 18 congressional seats, behind Ms Fujimori’s 73 and a leftist party’s 20.
Widely seen as honest, Mr Kuczynski caught up with Ms Fujimori in the final stretch of campaigning after he called her “a deadly threat to democracy” in a debate as she was stung by scandals involving her close advisers.