Keiko Fujimori conceded defeat to Pedro Pablo Kuczynski Friday in Peru's presidential election, promising a "responsible opposition" for his five-year term.
Liberal economist Kuczynski narrowly beat Fujimori, a right-wing populist who is the daughter of imprisoned former president Alberto Fujimori, in Peru's presidential run-off held Sunday.
Kuczynski emerged the winner with 50.12 per cent of the vote, while Fujimori, 41, garnered 49.88 per cent.
The margin - just 41,000 votes out of more than 17 million cast - was the closest race in Peru's history.
Fujimori called the count "confused" but said she would accept it "democratically."
She said she and her Popular Force party, which holds an absolute majority in Peru's Congress, would continue to fight for the interests of the more than 8.5 million Peruvians who voted for her.
Fujimori attributed her defeat to a "campaign of hate" that she said had been waged against her by political, economic and media elites.
A broad coalition of parties united behind Kuczynski to make the second-round election a virtual referendum on the elder Fujimori, whose authoritarian style many feared his daughter might revive.
Kuczynski said that he won't pardon the elder Fujimori, in prison for crimes against humanity, but he hasn’t ruled out signing a law that might help the former leader.
"I will not pardon him. If Congress presents a law for prisoners like him to finish the end of their jail sentences at home, I would sign it," Kuczynski said in comments published in the magazine Semana Economica.
"I don’t know if his supporters will want that. They want him to walk free but there has been a legal process," he went on.
Fujimori's supporters want an admission that the judicial system got it wrong and for the former head of state to walk free a vindicated man.
However, experts say there is no basis for such a request because Fujimori, who ran the country from 1990 to 2000, was found guilty in a fair trial of ordering 25 murders and two aggravated kidnappings in 1991 and 1992.
Kuczynski, who at 77 is the same age as the ex-president, expects the alternative might be a congressional law that allows the elderly or those with health problems to complete their jail sentences in their own homes.