Christian Oliva made his debut with the Nacional's first team during the Supercopa Uruguaya, an annual one-match football competition in Uruguay.
He made his professional debut late in the month, coming on as a second-half substitute for Luis Aguiar in a 31 loss against Penarol, for the year's Supercopa Uruguaya. In January 2018, after scoring 17 goals for the reserve side, Oliva was promoted to Nacional's first team by manager Alexander Medina, who also worked with him in the B-team. The Supercopa Uruguaya (Uruguayan Supercup) is an annual one-match football official competition in Uruguay organised by the Uruguayan Football Association (AUF) which is played between the Primera Division champions and the Torneo Intermedio winners of the previous season, starting from 2018. 
