(Bloomberg) -- With just four days left before Brazilians cast their votes, two polls placed front-runner Luiz Inacio da Silva within striking distance of an outright presidential victory in the first round.

Pollster Quaest said Wednesday the leftist challenger would get 50.5% of valid votes on Sunday, while PoderData placed him just shy of a definitive win with 48%. Excluding null and blank ballots, a candidate needs to break a threshold of 50% to avoid a runoff. 

All eyes are on whether Lula, 76, has the momentum to achieve a single-round victory over incumbent President Jair Bolsonaro on Oct. 2. Such a win has not happened in Brazil since 1998. Short of that, they will likely square off again on Oct. 30.

Lula, who benefited from a period of economic bonanza during his previous two terms in office, has been the heavy favorite since the Supreme Court cleared him of corruption convictions last year, enabling his latest run. 

With only about 2% of the electorate still undecided, Lula is making a final push to win over the political center. On Tuesday, he attended a dinner with some of the country’s top bankers and executives, the daily Estadao reported, and is set to dine with others this evening. 

Analysts say an outright victory by Lula largely depends on his his ability to peel off voters from long-shot presidential contenders. Support for candidates other than the current and former president makes up about 12% of all voting intentions.

Of those, nearly a quarter would be willing to switch their vote to ensure Lula wins in the first round, according to Felipe Nunes, the head of Quaest.

Bolsonaro, 67, appears to have stagnated in the last days of campaigning, with Quaest and PoderData placing him at 36% and 38% of valid votes in the first round, respectively. 

A major test for a last-minute change in preference will come on Thursday when the presidential hopefuls square off in the last televised debate before the vote.

Both pollsters show Lula handily winning in a second round.

The Quaest poll, commissioned by brokerage Genial Investimentos, interviewed 2,000 Brazilians between Sept. 24 and 27, with a margin of error of plus or minus 2 percentage points. PoderData spoke via phone with 4,500 people between Sept. 25 and 27 with a margin of error of 1.5 percentage points.

(Updates with Lula’s campaign events, debate and analysis throughout.)

©2022 Bloomberg L.P.