Besiktas manager Senol Gunes has said "something is wrong" with goalkeeper Loris Karius, who is at the club on loan from Liverpool.
The goalkeeper faced jeers from his own supporters on Sunday after he was at fault for one of the goals scored by Konyaspor in the Turkish Super Lig game between the two sides.
Despite the mistake, Besiktas were able to pick up a 3-2 win at the Vodafone Park Stadium, with Shinji Kagawa netting a winner for the team in stoppage time.
After the game, Gunes was critical of the player's performance and accused him of lacking passion for the sport, per Eren Sarigul of ESPN FC.