|Presidential candidate Jose Serra (C), of the Social Democratic Party , trails his rival in the polls [AFP]
Voting has opened in Brazil for a landmark presidential poll that opinion surveys suggest may see a female candidate being elected the country's president for the first time.
On the eve of Sunday's vote, four opinion polls showed Dilma Rousseff, the candidate of the ruling Workers' party, with a double digit lead over her rival Jose Serra.
Four opinion polls released on Saturday gave Rousseff a lead of between 10 and 13 percentage points, following a televised debate between the candidates late on Friday.
Rousseff struck a confident note on Saturday while speaking to reporters.
"I will govern for all Brazilians. There will be no discrimination of parties. I won't govern only for my coalition," she said.
Andre Vargas, communications secretary for the Workers' party, predicted a win for Rousseff with a comfortable margin.
"We should win with a minimum advantage of 10 percentage points and a maximum of 15 points," he said.
Al Jazeera's Teresa Bo, reporting from the city of Sao Paulo, said it had been an extraordinary campaign this time with none of the candidates matching the popularity of Luiz Inacio Lula da Silva, the incumbent president.
"We have seen a lot of aggression between both candidates. Jose Serra, the former governor of Sao Paulo, basically accused Dilma Rousseff of not being experienced enough, never being elected and also being involved in some corruption scandals.
"On the other hand, Jose Serra on a trip to Rio De Janeiro was physically attacked by members of the Workers Party. So there's been lots of tension in this campaign and people we have spoken to are very happy to see it come to an end in a way."
Both Rousseff and Serra wrapped up their campaigns in the key swing state of Minas Gerais, which in political circles is often referred to as "Brazil's Ohio", referring to the US state, because it has been an accurate predictor of previous presidential elections.
Since democracy returned to Brazil in 1985 after two decades of military rule, every president has carried the state, which has the country's second-largest electorate.
It has not all been smooth sailing for Rousseff. She failed to secure the presidency in the first round of voting on October 3, forcing the election into a second round run-off against Serra.
Rousseff's strong position in the polls is a rebound from several weeks ago when her campaign was hit by corruption allegations and questions over her religious beliefs.
But by focusing on eight years of strong economic growth under Lula, Rousseff - his former chief of staff - has been able to attract the support of crucial swing voters.
Many in Brazil say they support Rousseff because she has been endorsed by Lula, who remains popular with large sections of society.
"It was under President Lula that my children got the opportunity to study, which I never had," said Gumercinda Queiroga, 84, a supporter who greeted Rousseff before she embarked on a motorcade on the outskirts of Belo Horizonte.
"Today, I have two apartments and live with dignity," Queiroga, who promised to get up at dawn to vote for Rousseff, said.