To win over voters, he went on a pre-election spending spree, eliminating income tax for some 800,000 citizens, removing VAT levies from basic goods and granting cash payouts to millions.
Many of Mr Massa’s supporters, however, had more to say about Mr Milei than their chosen candidate.
“Milei was going to take away our rights, our abortion rights,” said Lucía, aged 32, celebrating on the streets with her friends. “We said no.”
“It was not a choice between Milei or Massa, it was a choice between being able to eat or not, and having free schools or not,” said Alva, aged 26.
At the polling stations earlier in the day, others indicated they were casting their vote for Mr Massa because he was the “lesser of two evils”.
“I’m voting Massa because the others are worse. I won’t be happy if he wins either, but at least he isn’t psychotic,” said Lisa, aged 59.