Bernd Schuster has resigned as coach of Besiktas, according to reports in Turkey.
National daily newspaper Hurriyet have reported that the German, who has previously coached Real Madrid, has stepped down from his post.
The Black Eagles have won just once in seven Super Lig games and are 21 points adrift of joint leaders Fenerbahce and Trabzonspor.
They are seven adrift of Kayserispor in the final Europa League qualifying spot available through the league, and were knocked out of this season's competition last month by Dynamo Kiev.
Their only real hope of silverware this season is in the domestic cup competition, where they have reached the semi-finals.
Schuster was quoted in Hurriyet as saying: ''I do not want to stay with a team that has failed.''
The newspaper are reporting that Tayfur Havutcu will lead the team until the end of the season, with Rafael Benitez named as a possible permanent successor to Schuster in the summer.