Samuel Eduok scored for Kasimpasa as they fell 4-1 to the potential Turkish Super Lig champions, Besiktas at the Vodafone Arena.
Eduok's strike turned out to be Kema Ozde's men consolation as they could not escape the heavy defeat against rampant Senol Gunes' side on Saturday.
Vincent Aboubakar had fired the home side in front inside the opening two minutes but Eduok brought the visitors back into the encounter two minutes later.
Ricardo Quaresma netted from the spot before Anderson Talisza and Ryan Babel’s strikes ensured the hosts outscored their visitors to seal maximum points and open a five-point gap atop.
The goal was the Nigerian's fourth in 27 games this season and the defeat leaves his side in seventh place on the log with 43 points - 14 adrift of Europa League places.
Kasimpasa will hope for a winning ways return against Antalyspor on May 27 before they face Genclerbirligi a week later.