Ghana defender Samuel Inkoon featured in Dunav Ruse's 4-1 defeat to Russian side Zhetsyu in a friendly on Tuesday.
Inkoom was making his second appearance for the club after joining in the winter transfer window.
The Bulgarian side are currently in Turkey on a winter training camp preparing for the resumption of the top flight league.
The 29-year-old joined the club last Tuesday after successfully undergoing a medical with the side following the decision by the world governing body FIFA.
He signed a six-month contract with the club and will stay with Danuv until the end of the season.