Henry Onyekuru's goal ensured Galatasaray retained the Super Lig title as Fatih Terim's men defeated Istanbul Basaksehir 2-1 at Turk Telekom Arena.
The top two teams went into the Sunday's fixture level on points with two games left to play, but Galatasaray's victory - giving them a superior head-to-head record over their nearest rival - means they can no longer be overtaken at the top.
Basaksehir briefly moved to the summit when they went 1-0 ahead, but Algeria international Sofiane Feghouli scored with a spectacular bicycle kick to level the match two minutes into the second half.
Onyekuru then headed home from close range in the 64th minute to earn head coach Fatih Terim his eighth Super Lig triumph with the club.
Galatasaray are champions in Turkey for a 22nd time, extending their record as the most successful side in the competition.