CORRECTED-GRAPHIC-Argentina's presidential rivals clash in key voter battlegrounds

(In Nov 13 story, corrects paragraph 19 to say Romina Viola intends to vote for Massa, not that she is an undecided voter)

By Lucinda Elliott

BUENOS AIRES, Nov 13 (Reuters) - As Argentines prepare to elect a new president, the two hopefuls vying for the keys to the Casa Rosada palace are focusing on undecided voters in key battlegrounds, with campaign pushes around capital Buenos Aires and central Cordoba province that could tip the balance in a tight race.

Center-left Peronist economy chief Sergio Massa faces libertarian outsider Javier Milei in the Nov. 19 vote, with polls suggesting a likely photo finish. Two wildly different visions for South America's no. 2 economy are on offer.

Milei offers potentially painful shock therapy for the embattled country that has run out of foreign currency reserves, has inflation over 100% and is set for a recession. Pragmatist Massa is pledging a unity government and more gradual change to solve the crisis that has worsened on his watch.

"People want to know who is the least bad of the two," said 31-year-old psychologist Fatima Gonzalez from the populous Buenos Aires province around the capital of the same name. She did not vote for Massa or Milei in October.

"Both are scary," said Gonzalez, adding that most people she knew were planning to cast their votes for Milei. "Many prefer to take the risk rather than carrying on with more of the same."

Massa pulled off a surprise win in the October first round, attracting 9.6 million votes, ahead of Milei on 7.9 million. There were nearly 10 million votes for other candidates, people who voted blank or spoiled ballots. Turnout was also historically low at under 78%.

'CAUSE MORE DAMAGE'

Many voters cited fears about Milei's "chainsaw" plan for the economy, including large public spending cuts. Over half the population of the country, where poverty is over 40%, rely on relatively generous social welfare payouts and subsidies.

"Deregulation always hurts the working classes more, so I think a Milei victory could cause much more damage," said Joaquin Gonzalez, 42, an architect from central Cordoba, who feared potential subsidy cuts and privatizations under Milei.

However, Milei has won over the public backing of conservative third-place finisher Patricia Bullrich - who had 6.3 million votes - and influential former President Mauricio Macri, lending the economist and former TV pundit some establishment support despite his vows to dollarize the economy and "burn down" the central bank.