UPDATE 1-Brazil's Rousseff closes in on Silva ahead of October vote
* Gap between runoff rivals down to 2 points- Datafolha poll
* Poll suggests President unhurt by Petrobras bribes scandal (Adds bribery scandal, background)
By Anthony Boadle
BRASILIA, Sept 19 (Reuters) - Brazilian President Dilma Rousseff has clawed back support at the expense of her main opponent in next month's presidential election, a poll showed on Friday, suggesting the runoff that should decide the vote is too close to call.
Marina Silva surged in the polls after joining the race on the death of her party's original candidate last month, and she appeared poised to unseat Rousseff with a 10 percentage-point margin in the likely second round vote.
But Rousseff has since recovered ground, aided by a TV campaign that has questioned Silva's ability to govern Latin America's largest nation and portrayed her pro-market policies as favoring the rich and hurting the poor.
Friday's Datafolha survey showed that, in a simulation of the likely runoff, the gap between them had narrowed to two points - 46 percent for Silva and 44 percent for Rousseff. That is equivalent to the poll's margin of error.
Rousseff widened her lead over Silva in the first-round vote to seven points, raising her support to 37 percent from 36 percent in the previous poll, while Silva fell to 30 percent from 33 percent. Centrist candidate Aecio Neves, the market favorite, has risen to 17 percent from 15 percent.
If no candidate wins a majority in the Oct. 5 election, the race will be decided in a runoff three weeks later between the two top vote-getters. Continuación...