The latest poll by Ibope showed Rousseff with 43 percent of the electorate's support. Yet on Monday, Standard & Poor's (S&P) downgraded Brazil's long-term debt rating to BBB minus, one notch above "junk" status. Brazil is rated BBB by Fitch and Baa2 by Moody's.
It is the latest blow to Rousseff who has struggled to revive the economy since the 2011 slowdown that has plagued her presidency since she succeeded Lula da Silva.
Regarding its decision, S&P wrote: "The downgrade reflects… the prospect that fiscal execution will remain weak amid subdued growth in the coming years," as well as "a constrained ability to adjust policy ahead of the October presidential elections".
Rousseff's first term: the verdict
The downgrade did not surprise analysts, as Rousseff has faced a difficult situation, with slowing economic growth coupled with a ballooning budget deficit and high inflation.
Carlos Caicedo, IHS senior principal analyst for Latin America, said Rousseff had tried to reverse these failing fortunes. "She introduced a number of tax cuts and the expectation was that they should have helped the economy," he told CNBC. "But it didn't. Fiscally, the country is in a weaker position."