On 2 November 2016, aged only 16, he made his senior debut with the reserves by coming on as a second-half substitute in a 1–2 Segunda División B home loss against Racing de Ferrol.
[3] Martínez made his professional debut on 31 May 2019, replacing goalscorer Xisco in a 3–2 away success over Córdoba CF in the Segunda División, as his side was already promoted.
[4] His La Liga debut occurred on 19 July of the following year, as he replaced fellow youth graduate Kike Barja late into a 2–2 home draw against RCD Mallorca.
[5] Martínez scored his first professional goal on 17 January 2021, netting the opener in a 2–0 away win over RCD Espanyol, for the season's Copa del Rey.
[8] Back to Osasuna in July 2024, he only featured in one league match before terminating his link on 8 January 2025;[9] hours later, he was announced at SD Eibar on a two-and-a-half-year deal.