On 16 July 2022 during stage 4 of the Giro della Valle d'Aosta Martinez along with teammate Reuben Thompson were the last men standing from the group of favorites. Martinez, who had just extended his lead gave the win to Thompson.[7] On 1 June 2022, Martinez got to ride for Groupama–FDJ as a development rider with the team at the 2022 Mercan'Tour Classic where he finished in eighth position, beating UCI WorldTour professional cyclists all while helping leader David Gaudu finish in fourth.[8] On 3 August 2022, Groupama–FDJ confirmed they had signed Martinez into their UCI WorldTeam for 2023.[9][10]
in June, 2023 Martinez took his first professional win at the Mont Ventoux Dénivelé Challenge. On 31 August 2023, during the 6th stage of the 2023 Vuelta a España, he was part of a large breakaway that went all the way to the finish in the Astrophysical Observatory of Javalambre. He came second in the stage behind Sepp Kuss (Team Jumbo–Visma), but enough to take the red jersey by 8 seconds ahead of Kuss. He became the youngest leader ever in the history of the Vuelta.[11][12] He also became the second youngest cyclist to wear a leader's jersey in a Grand Tour since 1904, at 20 years and 51 days, behind Henri Cornet's 19 years and 344 days in the 1904 Tour de France.[13]
