Mauricio Macri speaks to supporters in Buenos Aires on October 25.

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NEW: Daniel Scioli and Mauricio Macri are headed for a runoff in November

Candidates are vying to succeed Cristina Fernandez de Kirchner

CNN  — 

The race to succeed Cristina Fernandez de Kirchner as Argentina’s president is headed for a runoff, with her party’s candidate in a tight race with the outgoing mayor of Buenos Aires.

With more than 97% of polling places counted, Daniel Scioli of Fernandez’s Front for Victory coalition had won 36.86% of votes, while Mauricio Macri of the Let’s Change coalition had 34.33%, according to official results.

In third place at 21.34% was Sergio Massa, who earlier Sunday said his coalition, United for a New Alternative, did not get the numbers it was hoping for and was not in the top two.

According to the constitution, to win the presidency a candidate must either win 45% of the vote or have an advantage of 10 percentage points over their closest rival.

That means Macri and Scioli are headed for a runoff on November 22.

Fernandez was elected in 2007, succeeding her husband, Nestor Kirchner, who served one term. He died of a heart attack five years ago this week.

She won re-election in 2011.

Both Massa and Scioli, whom Fernandez endorsed as her successor, anticipated being in a second round of voting.

“It is an irreversible trend at a national level: There is a second round in Argentina,” Sen. Ernesto Sanz said from the headquarters of Let’s Change before the results began coming in.

Asked about the possibility of a runoff, Alberto Samid, vice president of the Central Market and a close confidante of Scioli, told CNN: “If there is a second round, we will win twice.”

A major issue in the election is whether the new leader will end the country’s fight against New York hedge funds, an unresolved debt debacle that has shut out Argentina from much of the global economy while suffering from massive inflation, declining cash reserves and major economic growth.

Journalist Francisco Fernández Funes contributed to this report.