Richmond Boakye Yiadom and Akwesi Frimpong played their first league matches for leaders Red Star Belgrade in their 2-0 win over Novi Pazar.
Both were handed starting roles as goals from Sran Plavisic and Marko Petkovic gave the capital side.
Frimpong, 23, joined the giants this transfer window from fellow Serbian top-flight side Napredak on a two-and-a-half year deal.
Striker Boakye is on an 18-month loan deal from Italian Serie B side Latina.
He scored five goals in three mid-season friendly matches including a hat-trick.