On 5 November 2016, Krstović made his first appearance of the 2016–17 season, entering the field during the second half of a 1–0 home league win over Bokelj.
[4] On 29 June 2017, Krstović appeared as a starter for Zeta wearing the number 9 shirt in a 1–0 away loss to Željezničar Sarajevo in the first leg of the 2017–18 UEFA Europa League first qualifying round.
On 25 February 2019, Krstović signed with Serbian club Red Star Belgrade until the summer of 2023 with an option for another year.
He made his debuts for the national under-21 team at the Valeriy Lobanovskyi Memorial Tournament in June 2017, appearing in both of his side's matches whilst scoring a brace in a 3–2 victory over Slovenia U21 in the third-place game.
[14][failed verification] Krstović scored his first international goal in his fourth appearance on 24 March 2023, to give Montenegro a 1–0 win away at Bulgaria in a 2024 European Championship qualifying match.