Born in São Paulo Gonçalo, Rio de Janeiro, Robert began his career at Fluminense Football Club. He was first included in their matchday squad on 3 November 2013, remaining an unused substitute in their Campeonato Brasileiro Série A 1–0 loss at Fla-Flu rivals Clube de Regatas do Flamengo. After only making three appearances on the bench in the following year"s national championship, Robert returned for the 2015 Campeonato Carioca, making five appearances including his first two professional starts. He scored in the penalty shootout on 18 April in which his team lost 9–8 to Botafogo de Futebol e Regatas in the semi-finals.
Robert went on to make four substitute appearances in the subsequent national league, scoring his first goal in the tournament on 4 October, an added-time consolation in a 3–1 loss at Santos Football Club. On 30 December 2015, Spanish treble champions Football Club Barcelona announced the signing of Robert, assigning him to their reserves in Segunda División B for the remainder of the campaign.