By Richard Lough
BUENOS AIRES (Reuters) - Challenger Mauricio Macri took the lead in Argentina's presidential election race against his ruling party rival, a poll showed on Sunday, two weeks before the Nov. 22 run-off vote.
The Management & Fit survey put Macri eight points ahead with the backing of 51.8 percent of voters, including a projected share of undecided votes. His rival, Daniel Scioli, had 43.6 percent support.
The numbers indicate Macri and his "Let's Change" alliance have maintained their momentum, after a surprisingly strong performance in the first round that stunned the ruling Front for Victory party and left Scioli scrambling to regain the initiative.
However, more than one in 10 of Argentina's 32 million voters are still undecided, leaving the presidential race open. Macri's lead narrows to six points with 46.3 percent of support when undecided votes are excluded from the candidates' count.
The outcome of the election will shape how the South American country tackles its economic woes, including high inflation, an over-valued peso and a central bank running precariously low on dollars.
Macri promises to start dismantling a raft of protectionist currency and trade controls on his first day in office if he wins, to open up Latin America's third biggest economy. Scioli says gradual reforms are required to lure new investment and labels Macri a neoliberal beholden to corporations and the rich.
Scioli has courted the 5 million voters of third-place candidate Sergio Massa with promises to increase pensions, scrap punitive taxes on corn and wheat exports and use the military to battle narco-gangs - all key Massa policy demands.
Even so, the poll showed that 57 percent of Massa's support will split toward Macri, favoring change over continuity after President Cristina Fernandez's eight years in power, which have been deeply divisive. Massa has not explicitly endorsed either candidate.
Scioli won 37.1 percent of votes in the first round and Macri defied pollsters to draw 34.2 percent support. The narrow margin was widely viewed as a slap in the face for Fernandez's brand of leftist populism and has forced Scioli to distance himself slowly from the outgoing leader.
The poll showed Fernandez's approval ratings fell three points to 38.8 percent from less than a month earlier.
Management & Fit polled 2,400 people nationwide between Nov. 1 and 5. The survey has a 2 percent margin of error.
(Editing by Larry King)