Emre Colak put the table-toppers ahead after seven minutes, only for Edin Visca to draw his side level after 14 minutes.
But Buyuksehir lost Pierre Webo to a red card four minutes before the interval and Colak (51), Milan Baros (72) and Selcuk Inan (90) all took advantage.
Trabzonspor defeated visiting Manisaspor 2-1, with Halil Altintop (40) and Burak Yilmaz (82) scoring either side of Isaac Promise's effort.
Bursaspor were 2-0 winners at Kayserispor as Pablo Batalla and Milan Stepanov found the target. Bursaspor played the last four minutes with 10 men following Musa Cagiran's sending-off.
Ankaragucu also picked up an away win, 2-1 at Mersin Idmanyurdu.
Ergin Keles scored in the first minute and added the winner in the 70th, just three minutes after Erman Ozgur had equalised.
Sivasspor eased to a 3-0 win over struggling Karabukspor, with Erman Kilic and Kadir Bekmezci netting before Michael Eneramo rounded off the scoring with a 75th-minute penalty.