The 2010 season saw him win further accolades as he ran a Dominican youth and junior record time of 46.19 seconds in June and a week later won the silver medal at the 2010 Central American and Caribbean Junior Championships. Held at Santo Domingo's Estadio Olímpico Félix Sánchez, Santos also won a relay bronze and knocked two and half seconds off the national junior record. Stepping up to the global stage, he came sixth in the final at the 2010 World Junior Championships in Athletics then achieved his first major victories at the Youth Olympic Games in Singapore, taking the 400 m and sprint medley relay titles.