Galatasaray reclaimed the Turkish Super Lig title after Fenerbahce's 2-2 draw at Istanbul Basaksehir - in which it had four men sent off - confirmed a 20th crown for its fierce rival.
Gala had done its part of the bargain, defeating Besiktas 2-0 at home thanks to goals from Yasin Oztekin and Wesley Sneijder.
That victory moved it six points clear of Fenerbahce, which was unable to take the title race into the final day as it imploded.
Istanbul Basaksehir went two goals up through Mehmet Batdal, before the latter stages of the clash saw remarkable scenes.
Diego pulled one back for the visitor in the 81st minute, but Fener then saw Mehmet Topuz sent off three minutes later.
Substitute Pierre Webo struck an equaliser with two minutes of normal time remaining but in stoppage-time, Bruno Alves conceded a penalty and was sent off, with team-mate Caner Erkin swiftly following for his protests.
The spot-kick was missed by Batdal, before Webo was dismissed right at the end as Fener ended the game with seven men and Gala was left to celebrate.
Besiktas's defeat means its hopes of qualifying for the UEFA Champions League are over and it must content itself with a place in the Europa League.
Istanbul Basaksehir, Bursaspor and Trabzonspor remain in the hunt for the final qualification spot.
Bursaspor defeated Akhisar Belediyespor 1-0 with Australia defender Aziz Behich playing a full game for the victor while Trabzonspor edged out Balikesirspor 3-2.
Already-relegated Karabukspor came from behind to defeat Sivasspor 2-1, two goals in four second-half minutes from Ahmet Ozek and Samba Sow clinching the win after Musa Yilmazer's opener.
Kayseri Erciyesspor fared less well, giving up a 3-1 lead at Kasimpasa to draw 3-3.
Elsewhere, Mersin Idmanyurdu came from behind to defeat Genclerbirligi 2-1; Gaziantepspor overcame Eskisehirspor 3-2 and Konyaspor drew 1-1 with Rizespor.