Argentina's president-elect Alberto Fernandez vowed on Monday to "turn the page" on the IMF-backed policies of incumbent Mauricio Macri, after voters weary of rising poverty and inflation swept the left back to power in Latin America's No. 3 economy. 

Argentina's electorate voted overwhelmingly on Sunday to ditch the economic liberalization and austerity of conservative Macri, which has left the commodities-rich nation teetering on the brink of a 100 billion U.S. dollar debt restructuring, and turned instead towards the Peronist left. 

Euphoria outside the campaign headquarters of Alberto Fernandez in Buenos Aires.  

Singing "we'll be back," the Peronist party's candidate in Argentina's presidential elections was declared winner in the first round of the elections after taking 48 percent of the vote on Sunday. 

"We began to turn the page today. This page (of Macri) will be forgotten and we will start writing another story on December 10 when we arrive with Cristina in government," Fernandez said after his election win, referring to his divisive running mate Cristina Fernandez de Kirchner. 

This victory for the Peronist party is down to the often divided politic movement throwing its full support behind one single candidate, Alberto Fernandez. But also part of the equation is the candidate for vice-president, former president Cristina Fernandez de Kirchner, who has been vital in securing millions of votes for this project. 

While the Fernandez-Fernandez duo celebrated on Sunday night, across the city was disappointment for Macri, who failed to secure a second term of office. 

"I want to congratulate the president-elect Alberto Fernandez. I have spoken to him for the excellent election that he had and I have invited him to breakfast as we must begin to plan the period of transition," said Macri. 

How Macri and Fernandez work together over the next few weeks will be key. With talks looming with creditors over 100 billion U.S. dollars in debts, reserves are dwindling, inflation is sky-high and rising poverty is sparking anger. 

In a bid to soothe markets, Fernandez and Macri signaled with their meeting on Monday that they would work together during the transition until the new government takes over in December. 

Treasury Minister Hernan Lacunza told reporters the two leaders had shared a "good dialogue" and there would be more meetings between the two teams in coming days. 

"(There is) total willingness from this outgoing government to work together in the transition," he said. Macri later said in a tweet that he and his team would be available to work with Fernandez to ensure a "democratic transition."

Markets are watching closely to see where Fernandez, a dark horse candidate who was a relative unknown until earlier this year, stands on key policies that could impact the peso, which crashed in August after he secured a landslide win in a primary vote. 

The return of the Peronists, and populist ex-president Kirchner, has startled some in Argentina and beyond, concerned that reforms to open Argentina more to global markets could be undone. 

"I'm worried because I already went through Cristina's government and it was very hard for farmers," said Sergio Storti, 58, a grains and cattle farmer in the bread basket province of Buenos Aires.

Markets on Monday were mixed, still uncertain how to respond to the result with many questions unclear. 

Argentina's central bank moved swiftly in the early hours of Monday to tighten capital controls during the transition and the peso closed 0.65 percent stronger. 

In the parallel black market, the local currency was more volatile, having fallen as low as 77 to the dollar, while Argentine over-the-counter bonds dipped 1.6 percent on average. 

(With input from Reuters)