BRASILIA (Reuters) -Brazilian President Luiz Inacio Lula da Silva is set to appoint the lawyer who defended him against graft accusations, Cristiano Zanin, to a vacant Supreme Court seat, Senate President Rodrigo Pacheco said on Thursday.

Zanin would replace Justice Ricardo Lewandowski, who retired in April, making him Lula's first nominee to the top court since taking office in January for a third non-consecutive term.

Zanin's nomination would still require Senate approval.

"I met with Cristiano Zanin yesterday. He will be the president's appointee for the Supreme Court and his nomination is expected to be submitted to the Senate today," Pacheco told reporters in Brasilia.

"I see his nomination positively. He has all conditions needed to be a Supreme Court justice," Pacheco added.

Zanin, a partner at law firm Zanin Martins Advogados, gained recognition in recent years for defending Lula against corruption charges, helping to throw out a conviction at the Supreme Court and release him in 2019 after 580 days in jail.

Zanin holds a law degree from the Pontifical Catholic University of Sao Paulo and has previously taught law at the FADISP college.

He has described himself as a specialist in bet-the-company litigation and "lawfare," or the misuse of legal proceedings to attack or intimidate opponents. He co-founded a think tank, the Lawfare Institute, and has published books about the theme.

(Reporting by Gabriel Araujo in Sao Paulo and Ricardo Brito in Brasilia; Editing by Steven Grattan, Brad Haynes and Mark Porter)