In doubles, Demoliner won two Challenger titles in 2009. However, only in 2012 formed a fixed partnership with João Souza, aiming to become an ATP-level doubles player. The partnership began in September and quickly obtained good results: five Challenger finals in a row, with two runners-up (Cali and Quito) and three titles (Campinas, Rio de Janeiro, and Porto Alegre). With this, Demoliner was approaching the top 100 at doubles.
