BRASILIA (Reuters) - Brazil's ruling party candidate Dilma Rousseff has widened her lead in October's presidential race over opposition candidate Jose Serra, a poll showed on Friday.
It is the biggest advantage any poll has so far given Rousseff, who in December trailed former Sao Paulo state governor Jose Serra by as much as 20 percentage points.
Rousseff, a career civil servant from President Luiz Inacio Lula da Silva's Workers' Party, got 41 percent of voter support with 33 percent for Serra, according to the Vox Populi poll released by TV Bandeirantes.
The same poll in June showed Rousseff ahead with 40 percent support against 35 percent for Serra.
Former Environment Minister Marina Silva remained unchanged with 8 percent.
With only two and a half months left to the October 3 election, investors are closely watching to see whether either candidate can maintain a significant lead.
Over the past three months Rousseff and Serra have been in a virtual tie, with poll results fluctuating in response to their campaign advertisement on TV.
None of the three leading candidates is seen as breaking with the mostly market-friendly policies that have helped Brazil's economy become a favorite on investors' global radar screen.
This year the economy is expected to grow by around 7 percent,the fastest economic expansion in 24 years.
The Vox Populi survey has a 1.8 percentage point margin of error and polled 3,000 people between July 17 and 20 and had a margin of error of 1.8 percentage points.
(Editing by Xavier Briand)