Darko Kostić

Darko Kostić (, (Ntarko Rallis); born 30 September 1978) is a Serbian–Greek professional basketball coach and former player.

Playing career Rallis had two stints with the Belgian team Okapi Aalstar where played during 1998–99 and 2000–01 season. In between he played for the German team Ratiopharm Ulm. In 2003, he moved to Slovakia where he played for two seasons for Chemosvit Svit and MBK Lučenec. Also, he played for the Ecuadorian team Salesianos Club Guayaquil.

On 2 November 2011 Rallis signed for Doxa Lefkadas of the Greek A2 League. He also played for the Greek A2 League teams Ermis Lagkada, and Livadeia.

Coaching career Prior to the 2016–17 season Kostić was named as a head coach of OKK Beograd after one year he spent there as an assistant coach of the head coach Vlade Đurović. He left the club in June 2018.

On 30 July 2018 Kostić became a head coach for Bulgarian team Academic Bultex 99. On 27 December 2018 Academic parted ways with him following the loss against Beroe.

On 4 January 2019, Kostić was named as a head coach of Vršac of the Basketball League of Serbia. In February 2020, he left Vršac.

On 16 June 2020, Kostić became a head coach for Novi Pazar.

On 13 Jaunuary 2026, Kostić became a head coach for KK Borac Zemun