Galatasaray won the Turkish league title for the 17th time on Saturday with a 2-0 win against Genclerbirligi Oftas, wresting the championship back from their Istanbul rivals Fenerbahce.
The victory in the final match of the season lifted Galatasaray to 79 points, six ahead of second-placed Fenerbahce, who lost 2-0 at Trabzonspor.
Galatasaray fans poured into Istanbul's streets, singing club songs, sounding car horns and waving red-and-yellow flags after the final whistle at the club's ageing Ali Sami Yen stadium, where 20,000 supporters watched the team parade the trophy.
Galatasaray took the lead in the 36th minute when Arda Turan sped down the right wing and crossed for veteran striker Hakan Sukur to score with a simple tap-in.
Defender Hakan Balta made it 2-0 just before halftime with a powerful volley from outside the penalty area.
Galatasaray's success came as a surprise to many, with injuries depriving the club of two key foreign players this season - Tobias Linderoth and Lincoln.
The club has also been rocked by internal strife which prompted German coach Karl-Heinz Feldkamp to resign at the start of April, citing differences with the management.
Cevat Guler took over in a caretaker role but it is not clear who will take the helm next season, when both Galatasaray and Fenerbahce will represent Turkey in the Champions League.
"There may have been times in recent weeks when the fans didn't think we would be champions... but we are delighted and thank everyone for their support," Guler said.
A key moment in the title race came two weeks ago when Galatasaray beat Fenerbahce in their derby match.
It was a bitterly disappointing end to the season for Fenerbahce who reached the quarter-finals of the Champions League before losing to Chelsea.
There was also disappointment for Sivasspor who were pipped for a place in the UEFA Cup by Besiktas because of Fenerbahce's defeat. All three teams have 73 points but Sivasspor came fourth by having the worst average in matches between the three sides.
Kayserispor take the other place in the UEFA Cup because of their Turkish Cup victory on Wednesday.