Gelson Martins did his pre-training at Benfica (2008-2010), but it was with the rival club Sporting CP that the native of Cape Verde climbed the ladder to professional football. After having accumulated 45 caps with the national youth teams, he started with the senior squad in 2016, just after the Portuguese victory at Euro. A year earlier, he was taking his first steps in the first team with Sporting. 140 games, 27 goals and 21 caps later, the fast striker joined Atlético Madrid in the summer of 2018. It was from the Madrid club that Gerslon Martins signed with AS Monaco in January 2019, under the form of a loan.