| BELO HORIZONTE, Brazil
BELO HORIZONTE, Brazil Brazil's presidential candidates rallied in the key swing state of Minas Gerais on Saturday in a last-ditch attempt to win over undecided voters before Sunday's runoff election.
With a double-digit lead in opinion polls over the opposition candidate, Jose Serra, the ruling party's Dilma Rousseff displayed an air of confidence she had not shown since she fell short of victory in the October 3 first-round vote.
"I will govern for all Brazilians. There will be no discrimination of parties. I won't govern only for my coalition," a beaming Rousseff told reporters in the state capital Belo Horizonte in what sounded like an early victory speech.
Four separate polls released on Saturday showed Rousseff with a lead of between 10 and 13 percentage points over Serra.
Datafolha, the most reputable of the polling firms, had Rousseff with 51 percent voter support against Serra's 41 percent.
Rousseff, President Luiz Inacio Lula da Silva's former chief of staff, appeared to have cleared the last obstacle to victory as she cruised through an uneventful TV debate on Brazil's most-watched TV channel late on Friday.
Her aides were brimming with optimism on Saturday.
"We should win with a minimum advantage of 10 percentage points and a maximum of 15 points," said Andre Vargas, communications secretary of Rousseff's Workers' Party, or PT.
Across town from Rousseff, Serra spearheaded his own motorcade, waving to supporters at the end of a four-month campaign in which his platform of clean and lean government failed to catch on with most Brazilians, who are happy with the boom years under Lula.
Both candidates wrapped up their campaigns in Minas Gerais, which in political circles is often referred to as "Brazil's Ohio," because it has been an accurate predictor of presidential elections.
Since democracy returned in to Brazil in 1985 after two decades of military rule, every president has carried the state, which has the country's second-largest electorate.
Members of Serra's PSDB party have touted Minas Gerais as the biggest pool of potential swing voters that could help him stage an upset on Sunday.
"The vote is not over. There's a part of the electorate that is not convinced of its vote," said Aecio Neves, the state's outgoing governor and a senator-elect for the PSDB.
But the number of undecided voters nationwide dropped to only 4 percent in an opinion poll on Friday from twice that earlier in the week.
Even if all undecided voters in Minas Gerais cast ballots for Serra, Rousseff would still win, said Marcos Coimbra, head of the Belo Horizonte-based polling firm Vox Populi.
The latest opinion polls show Rousseff ahead of Serra by 11-15 percentage points, a strong rebound from several weeks ago when her campaign had wobbled on corruption allegations and doubts over her religious beliefs.
Her recovery came as she steered the discussion back to the eight years of strong economic growth under Lula, whose endorsement transformed her from a largely unknown bureaucrat into a presidential favorite.
"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," said Queiroga, who promised to get up at dawn to vote for Rousseff.
(Writing by Raymond Colitt; editing by Todd Benson and Christopher Wilson)