The Lions were also knocked out of the Europa League last week.
Denizli has resigned from last year’s league champions after a three-month spell with the troubled Istanbul club. He had taken charge in November 2015 after former coach Hamza HamzaoÄŸlu stayed less than a year at the helm.
Denizli, 66, previously managed the Turkish national team for four years and reached the quarter-finals of Euro 2000.
He has also won three domestic league titles with each of Istanbul’s arch-rivals – Galatasaray, Fenerbahçe and BeÅŸiktaÅŸ.
To compound Galatasaray’s tough season, the club may be given a ban from continental competition from Europe’s ruling body UEFA later this week over its failure to follow financial fair play rules.