Trabzonspor's defeat to Konyaspor left Basaksehir four points clear with a match to play, becoming the sixth club to clinch the title.
Basaksehir have won the Turkish Superlig for the first time on Sunday, snapping the dominance of the city's 'Big Three' clubs Fenerbahce, Galatasaray and Besiktas.
Basaksehir, formerly the Istanbul municipality team established in 1990, captured the title after a 1-0 win over Kayserispor. Second-placed Trabzonspor lost 4-3 to Konyaspor.
Basaksehir –– the sixth club ever to win the Superlig since its inception in 1959 –– top the standings with 69 points, seven ahead of Trabzonspor with one round left.
Sivasspor were third, with Besiktas, Galatasaray and Fenerbahce in fourth, fifth and seventh respectively.
Playing in an empty stadium under novel coronavirus-related restrictions, Basaksehir's players hugged and cheered after the game, which was interrupted twice by power outages.
TV footage showed fans, who watched the game on big screens sitting in plastic chairs outside the stadium, celebrating as the Trabzonspor match ended, before the final whistle blew in the Basaksehir game.
They lit torches, hugged and chanted, waving flags in Basaksehir's orange and blue colours outside Fatih Terim stadium.
Basaksehir stands in marked contrast to the city's 'Big Three' clubs - Fenerbahce, Galatasaray and Besiktas, who have won the Superlig title 54 times between them.
The Big Three have huge fan bases while Basaksehir have few supporters to fill the stands in their 17,000 capacity stadium.
Their name was changed to Basaksehir in 2014 when they moved to a new stadium in the Istanbul district of the same name.