Rangers saw off Old Firm rivals Celtic, while Hearts won the Edinburgh showdown on Scottish Premiership derby day.
Ryan Jack fired the only goal in a 1-0 victory at Ibrox as Rangers claimed their first league triumph over their bitter rivals since March 2012.
It was a result that ended Brendan Rodgers' run of derby dominance - 10 wins and two draws since his move to Celtic Park - and one that lifts Rangers level on points with the champions, although they have played a game more.
While Gers could celebrate in Glasgow, Hearts claimed superiority in Edinburgh as Olly Lee's spectacular strike sealed a first win over Hibernian at Easter Road since April 2014.
Lee turned and fired into the top corner in the 28th minute and Hearts survived some late pressure to climb into fifth - seven points clear of their eighth-placed rivals.
Two goals in the opening 11 minutes kept Kilmarnock in touch with the Old Firm as they beat St Mirren 2-1.
Stuart Findlay opened the scoring four minutes in and Jordan Jones added the second. Alfie Jones (22) pulled one back quickly but that was the end of the scoring.
A first-minute goal from Scott Tanser set St Johnstone on their way to a 2-0 win at bottom side Dundee, Liam Craig making it safe just prior to the hour mark.
There were three goals in the last 20 minutes as Aberdeen won 2-1 at Livingston, James Wilson (71) and Alan Lithgow's own goal putting the Dons ahead before Ryan Hardie made for a tense finish.
Tom Aldred won it for Motherwell as they were 2-1 victors at Hamilton, who had led through Dougie Imrie before Aldred pulled one back.