Brazil's Rousseff could win in first round: poll

Presidential candidate of the Workers' Party Dilma Rousseff greets supporters during a campaign rally in Rondonopolis, Brazil's Mato Grosso State August 24, 2010.

BRASILIA (Reuters) - Brazilian ruling party candidate Dilma Rousseff opened a 24-percentage point lead over her main presidential rival in an opinion poll on Saturday, staying on course win the October 3 election in the first round.

Career civil servant Rousseff has 51 percent support, against former Sao Paulo state governor Jose Serra's 27 percent, according to an Ibope survey published in O Estado de S. Paulo newspaper.

Rousseff, President Luiz Inacio Lula da Silva's former chief of staff, has overtaken Serra in his home state of Sao Paulo, which has the country's largest electorate. She leads there 42 percent to 35 percent, the poll showed.

She has doubled her overall margin on Serra since the previous Ibope poll published on August 16, when she led 43 percent to 32 percent. She has taken a clear lead in three other polls as well.

Rapid economic growth this year and promises to continue with the policies of Lula, the most popular Brazilian president in recent decades, have helped increase Rousseff's ratings.

But her lead over Serra got a further boost since the campaign slots started on television this month that have linked her closely with Lula, bringing a first-round victory on October 3 with more than 50 percent of votes within reach.

The ads have given many voters their first in-depth look at Rousseff, who was little known by the Brazilian public only a couple of months ago. She trailed Serra in the polls as recently as June.

Saturday's poll showed her getting 59 percent of valid votes once spoiled and blank ballots are discarded, as they are on election day.

In Minas Gerais, considered a vital "swing" state and home to the country's second largest electorate, Rousseff leads Serra by 51 percent to 25 percent, the poll showed.

Support for former Environment Minister Marina Silva, the candidate for the Green party, fell to 7 percent from 8 percent in the previous survey.

Neither Rousseff nor Serra is seen breaking with mostly market-friendly policies that have brought Brazil economic stability and made it an investors' favorite.

But both favor a strong government hand in the economy, and Rousseff wants to further strengthen state companies in the oil, energy and banking industries.

Ibope interviewed 2,506 people for the poll which has a margin of error of plus or minus 2 percentage points.

(Reporting by Ana Nicolaci da Costa; editing by Mohammad Zargham)