Brazilian President Dilma Rousseff highlighted her government's achievements in reducing poverty while her rival used Sunday night's presidential debate to attack her on allegations of bribery in state-run oil company Petrobras.

Opposition candidate Aecio Neves grilled Rousseff over a growing kickback scandal at Petrobras, where a former top executive has told investigators he helped operate a long-running scheme that funneled money back to Rousseff's Workers' Party.

"Why in all the years was no action taken to prevent this from continuing?" Neves asked.

Rousseff ran the administrative council of Petrobras between 2003 and 2010 when she was minister or energy and mines and later chief of staff of the presidency.

The president, in turn, defended her performance and said she fired the executive involved and ordered an investigation.

Rousseff also highlighted how little Neves' Social Democratic Party invested in social programs when it governed Brazil from 1994 to 2002. She contrasted that with the spending by herself and her Workers' Party predecessor, Luiz Inacio Lula da Silva, which she said lifted 42 million Brazilians out of poverty.

Rousseff and Neves received 42 percent and 34 percent respectively in the first round of voting on Oct. 5. They meet in a runoff on Oct. 26, with polls showing them in a technical tie.