The Italian says he left the club due to a dispute concerning their future plans, while he also backed Didier Drogba to perform at the top level for another season
The Italian's departure from the club by mutual consent was confirmed on Wednesday.
And the former Inter and Manchester City coach has said he left the club due to a dispute over the future direction of the club.
"The targets were changed from those set in October when I arrived so, by mutual agreement, we decided to terminate our relationship," the 49-year-old told Sky Sport Italia.
"We had a good relationship for those eight months, I had a great time in Instanbul."
The Italian also backed 36-year-old Didier Drogba, who has confirmed he will also leave the club, to have a big impact wherever the Ivorian decides to play his football next season.
"Drogba is a great guy and can make the difference, if not for 50 games," said the former Manchester City boss.
"I don't if Juventus or any other teams are interested in him, but for 20-25 games he can still make the difference. Time catches up with everyone, but he can still be useful."
Mancini claimed the Turkish Cup and finished the league campaign as runners-up to Fenerbache during his short stay with the club and has been linked with a return to former sides Sampdoria and Lazio.