Kasımpaşa suffered their first loss of the season following the 1-0 loss against Gençlerbirliği at the 19 Mayıs stadium.
The Istanbul minnows also conceded their first goal this season in the process.
On-loan Super Eagles and Chelsea defender Kenneth Omeruo started for the Istanbul based side but was unable to help his side keep their third consecutive clean sheet.
The Nigerian international joined Kasımpaşa on-loan last month and the Istanbul based side have a buyout clause option.
The 21-year-old spent last season on loan at Middlesbrough who missed out on Premier League promotion.
