[2] On 8 February 2024, after already playing three senior matches in the Copa FGF, he signed a new contract with the club until 2028.
[3] Gustavo Nunes made his first team debut on 11 February 2024, coming on as a first-half substitute for injured Jhonata Robert and providing the assist for Everton Galdino's equalizer in a 1–1 Campeonato Gaúcho home draw against São Luiz.
[4] He scored his first goal six days later, netting the opener in a 6–2 home routing of Santa Cruz-RS.
[5] Gustavo Nunes made his Série A debut on 14 April 2024, replacing Yeferson Soteldo in a 2–1 away loss to Vasco da Gama.
On 28 August 2024, it was announced that Gustavo Nunes had joined Premier League side Brentford on a six-year deal, with an additional two-year option.