Conservative opposition candidate Mauricio Macri has won Argentina’s presidential election, ending 12 years of leftist rule.

Macri promised that a “marvellous” new era was starting for the country after he won the run-off vote on Sunday.

“This is a historic day, a change of era which is going to be marvellous,” Macri told cheering supporters after ruling party candidate Daniel Scioli conceded defeat.

Official results gave Macri 51.4 percent of the votes and 48.6 percent for Scioli, with 99 percent of ballots counted.

Macri’s win ends a political era dominated by Cristina Fernandez de Kirchner and her late-husband Nestor Kirchner.

“I want the country to grow. Our children had to leave because of the economic situation and we want them to return,” a voter giving her name only as Susana told Al Jazeera.

Scioli conceded defeat on Sunday. However, Daniel Schweimler, reporting from Scioli’s headquarters, said supporters of the ruling party “are finding it difficult to accept the defeat”.

Neither candidate achieved the 45 percent of votes needed to avoid a runoff in the first round of the election held in October.

Scioli picked up 35 percent of the vote, with Macri a percentage point behind with 34 percent.

Macri had promised a break from Kirchner’s leftist economic policy, promising a more business-friendly environment in the country, while Scioli prioritised policies aimed at helping Argentina’s poorest.

Kirchner has ruled the country since taking over from Nestor in 2007, and has reached the end of her two-term limit.

Despite early fiscal success, Argentina’s economy has started to flounder, and Macri will inherit a litany of financial problems.

The country is facing inflation and is involved in a legal battle against two American hedge funds that reject its plans to restructure the $100bn in debt it defaulted on in 2001.

The firms, which Kirchner condemns as “vulture funds”, successfully sued for full payment in US federal court. Kirchner’s refusal to pay them pushed Argentina into a new default last year.