Mateus de Sá first competed in triple jump competitions in 2012, at that time also in long jump, at national level. That year he won several medals at Brazilian youth and junior championships and qualified in the triple jump for the U18 South American Championships in Mendoza, Argentina, where he won with a width of 15.26 m. In the following year he started in the next higher age group and was also able to qualify for the U20 South American Championships, which again took place in Argentina, this time in Resistencia. There he won the silver medal with a jump of 16.14 m. A month earlier, he had jumped over the 16-meter mark for the first time.
In 2014 he took part in the U20 World Athletics Championships in Eugene. There he won the bronze medal with 16.47 m. Two years later he started at the U23 South American Championships in Lima. As in the previous season, he was unable to confirm the distances he had already jumped, but was still able to win the bronze medal. It was not until 2017 that he was able to build on previous widths. At the beginning of June he set his best performance with 16.87 m. In the same month he was able to win the silver medal at the South American Championships in Asunción. With his achievements he qualified for the World Championships in London. There he jumped only 16.10 m in the qualification and finished 27th. Also in August he started as a student at Santa Anna University in São Paulo at the Universiade in Taipei, where he finished eighth.
In 2018 he won the silver medal at the South American Games in Cochabamba in Bolivia with 16.78 m . In 2019 he won the silver medal at the Universiade in Naples. At the first indoor South American Championships in 2020 in Cochabamba, Bolivia, de Sá won the silver medal with an indoor performance of 16.62 m.
Brazil
Mendoza
Eugene
Lima
Asunción
London
Taipei
Cochabamba
Naples