Jair Bolsonaro (pictured) could return to a role in government under his son, Flavio Bolsonaro, when the latter wins the presidential election. (EPA Images pic)

BRASILIA: The biggest winner in Brazil's blockbuster weekend election did not even appear on the ballot.

Banned from public office, former President Jair Bolsonaro is under house arrest, serving a 27-year sentence for a coup plot after his 2022 election loss.

The 71-year-old watched from confinement on Sunday as his eldest son, Senator Flavio Bolsonaro, scored an upset victory over leftist President Luiz Inacio Lula da Silva in the first round of the presidential election.

The result, which pundits linked to a right-wing wave sweeping the region and Lula's own campaign missteps, made Flavio the favorite to win second-round voting on Oct 25. The shock victory represented a stunning reversal of his father's fortunes as the rehabilitated Bolsonaro family and ideological movement emerged stronger than ever.