BRASILIA, Sept. 17 (Xinhua) -- Brazilian right-wing presidential candidate Jair Bolsonaro leads pre-election polls as leftist hopeful Fernando Haddad shows momentum, according to a nationwide survey released on Monday.

Polling firm MDA said Bolsonaro, the candidate of the conservative Social Liberal Party (PSL), garnered a significant 28.2 percent of the votes for a more than 10-point lead over his closest rival, Fernando Haddad of the progressive Workers' Party (PT).

While Haddad garnered only 17.6 percent of the votes in the poll leading up to Oct. 7 general elections, the survey confirms he is fast gaining ground on Bolsonaro, despite arriving late to the race.

Haddad's candidacy was just announced on Sept. 11, after the PT's original pick, ex-president Luiz Inacio Lula da Silva, bowed out of the race.

Lula had been campaigning from his jail cell, where he is serving a 12-year sentence for corruption, hoping an ongoing appeals process would allow him to run for reelection.

With just three weeks to go before the elections, trends indicate the battle may be shaping up between Bolsonaro and Haddad.

Bolsonaro, known for praising Brazil's former military dictatorship, is currently convalescing in the hospital after he was stabbed in the abdomen during a campaign rally.

On Monday, the hospital issued a report saying he was in stable condition following emergency surgery, and had been moved from the intensive-care unit to semi-intensive care.

Another 11 candidates are in the running, including a former governor, Ciro Gomes, who is in third place, with 10.8 percent of the votes.

According to the MDA's survey, an expected runoff would see Bolsonaro defeat Haddad by 39 percent versus 35.7 percent.

The poll commissioned by the National Transport Confederation (CNT) queried 2,002 registered voters across the country from Sept. 12 to 15, and has a 2.2-point margin of error.