Neves and Rousseff after a television debate in Sao Paulo.

Brazilian President Dilma Rousseff pulled ahead of opposition candidate Aecio Neves in another poll yesterday and looks like a slight favourite heading into what is expected to be the country’s tightest election in decades.

The Datafolha poll was the fourth in three days to show Rousseff approaching Sunday’s runoff vote with a slight edge over Neves, who had stirred investor enthusiasm by promising business-friendly policies to revive a sluggish economy.

Brazil’s stocks and currency have sold off this week as Neves lost momentum.

In contrast to the pessimism in financial markets, voters surveyed by Datafolha expressed a surge of optimism about Brazil’s economy, suggesting Rousseff’s well-oiled campaign was restoring confidence despite a recession this year.

In the new survey, Rousseff’s share of voter support has risen to 47% from 46% in a Datafolha poll published on Monday. Support for Neves remained at 43%.

Neves dismissed recent surveys on Tuesday, noting that for the October 5 first-round vote, pollsters had underestimated his support and overestimated Rousseff’s by a margin of 10 points.

While Rousseff has widened her lead to 4 percentage points, the difference between them is still within Datafolha’s margin of error of plus or minus 2 percentage points.

Excluding undecided voters and spoiled and blank survey responses, Rousseff has 52% support against 48% for Neves, the poll showed, the same result as on Monday.

Rousseff has gained ground by reminding voters of the rising wages and expanding social programmes many have enjoyed over the past 12 years of Workers’ Party rule, drawing on the charisma of her mentor and predecessor Luiz Inacio Lula da Silva.

Neves’ rejection numbers have edged up in polls in recent weeks as Rousseff repeatedly said her rival would govern for the elite and cut back the vaunted social programmes that have become synonymous with the Workers’ Party.

Neves insists he would preserve those programmes while curbing other government spending, taming inflation and ending what he calls heavy-handed industrial policies in order to restore investor confidence. But his message may be losing traction as voters’ outlook brightens.

Just 15% of Brazilians in Datafolha’s latest survey expected the economy to worsen, down from 25% in late September and 36% in early June. About a quarter worried that unemployment would increase, down from more than a third last month and half of those surveyed in June.

As a result, Neves’ criticism of Rousseff may be backfiring. He has accused her of mismanaging the economy and standing by as a corruption scandal rocked Brazil’s largest company, state-run oil producer Petroleo Brasileiro, but neither issue seems to be changing many voters’ minds.