Martínez's record-breaking continued into 2014, as he jumped a world youth best of 17.24 m in front of a home crowd in the Cuban capital Havana. He then broke the World Junior Championship record twice at the 2014 World Junior Championships in Eugene, Oregon, jumping 17.08 m with a 0.6 m/s headwind on his first attempt and 17.13 m with a 0.7 m/s headwind on his second attempt. He became the fourth Cuban world junior champion in the triple jump after Yoelbi Quesada in 1992, René Hernández in 1996, Arnie David Giralt in 2002 and Pedro Pablo Pichardo in 2012.