[1] On 20 December the following year, he made his senior debut by coming on as a 62nd-minute substitute for Bogdan Gavrilă in a 1–1 Liga I draw against CFR Cluj.

On 30 July 2017, he scored his first Dinamo goal upon his return to Bucharest in a 1–0 away victory over Liga I defending champions Viitorul Constanța.

[4] During early November 2017, it was reported that Costache would be joining CFR Cluj in the approaching transfer window for a fee of €1 million.

[6] Over the course of four and a half seasons in Cluj-Napoca, Costache amassed totals of 145 games and 15 goals in all competitions, and also aided to seven domestic honours.

[7] On 22 August 2023, Costache signed for Cypriot First Division club Apollon Limassol on a two-year deal with the option for a further year.