Ange Postecoglou guided Celtic to the cinch Premiership title at the first time of asking despite drawing 1-1 at Dundee United.
The Hoops, who went into the game six points ahead of reigning champions Rangers with two games to play, took a 53rd-minute lead through Giorgos Giakoumakis' 15th goal of the season.
However, they were forced to make do with a 1-1 draw at Tannadice when United, who had twice hit the post in the aftermath of the opening goal, levelled courtesy of Dylan Levitt's piledriver.
That proved sufficient to extend their unbeaten league run to 31 games and secure a 10th title in 11 years, capping a spectacular turnaround after they finished last season 25 points adrift of their neighbours.
Europa League finalists Rangers went into their home clash with Ross County knowing their reign as champions was effectively at an end, but nevertheless emerged with a 4-1 victory.
Scott Wright's 13th-minute opener and a 29th-minute James Tavernier penalty put the home side in the driving seat and, although Jordan White pulled one back, fellow substitutes Fashion Sakala and Amad Diallo killed off any hope of a fightback.
Ricki Lamie's second-half goal saw Motherwell leapfrog Dundee United in the race for Europa Conference League qualification with a 2-1 victory over Hearts.
Joseph Efford put the home side ahead after just three minutes, but Josh Ginnelly gave the visitors hope before Lamie won it 11 minutes after the break.
Callum Hendry's early goal handed St Johnstone a morale-boosting 1-0 win over Aberdeen which confirmed bottom-of-the-table Dundee's relegation, while St Mirren and Livingston played out a 0-0 stalemate at the SMiSA Stadium.
