 On 13 August 2018, Martínez joined CF Rayo Majadahonda still in Spain's second division, on loan for the season.He made his debut six days later on the opening weekend of the season against Real Zaragoza, Majadahonda's first game at this level.On as a second-half substitute for Enzo Fernández, he scored the club's first goal in the Segunda División, albeit in a 2–1 defeat.