Besiktas on Thursday parted ways with coach Sergen Yalcin after a dreadful run of form both domestically and in the Champions League in which they failed to register a point.
The Istanbul side won their 21st Turkish title last season and had high hopes for a campaign played out in front of fans for the first time since the start of the coronavirus pandemic.
But they have lost five straight league matches and sit ninth in the table.
The club said they were parting ways with Yalcin “by mutual agreement” and thanked him for leading the black-and-whites to a Turkish Cup and Super Lig double last season.
The 49-year-old former Turkish international had been in his post since January 2020.
The club announced no immediate permanent successor.