Lula, serving a 12-year-sentence for corruption and money laundering, is the front-runner despite being in jail.
But barring dramatic events - the judges can reconsider their decision after the vote of the last two magistrates - the former president, who is best known as Lula, cannot run for a third term.
While casting the final vote to nail the coffin on Da Silva's Presidential ambition, Supreme Court Justice Luis Roberto Barroso said the law was simple and clear; it forbids candidates whose conviction has been upheld on appeal from contesting for public office in Brazil.
Moments later his Workers' Party (PT) vowed to "fight with all means to secure his candidacy".
"This is a week that will shame the judiciary forever", the party said in a statement to The Guardian, arguing that the clean slate law only banned candidates after all appeals processes were exhausted.
He relied on Lula's recent backing from the UN Human Rights Committee, which ruled that the former leader can not be disqualified from the elections as his legal appeals are ongoing.
"We will present all appeals before the courts for the recognition of the rights of Lula provided by law and global treaties ratified by Brazil", said the party in a statement. By law, the former president is barred from running because his conviction has already been upheld by one appeals court.
Lula's case was a last-minute addition to the Superior Electoral Court's extraordinary session, where seven magistrates in Brasilia began hearing it at 5:00 pm (2000 GMT).
The former trade union leader vehemently denies the accusations and has dismissed the charges as a political plot aimed at preventing him from standing in the elections.
If da Silva is barred, former Sao Paulo Mayor Fernando Haddad is seen as his likely candidate for the presidency.
Polls show tepid support for the vice presidential running mate Haddad's bid, but the party hopes Lula's popularity could boost the former mayor's hopes.
Despite the uncertainty over his ability to stand, Lula now leads polls with more than double the share of his nearest challenger, the right-winger Jair Bolsonaro.
Lula's social media followers remain upbeat, though.