Rangers snatched a late winner at Motherwell to ensure Celtic will have to wait at least another week to clinch the title, while there were also wins for Dundee United, Hearts and St Mirren.
Celtic were unable to secure the league crown last week after being losing the Old Firm derby at Ibrox but would have had the opportunity to celebrate in front of their own supporters by beating St Johnstone on Sunday, if Rangers had failed to pick up three points against Motherwell.
Motherwell were also looking to draw level on points with Rangers in second and opened the scoring through Henrik Ojamaa after six minutes, but Steven Whittaker quickly equalised and Lee McCulloch fired home in the 89th minute to make it 2-1 to Ally McCoist's men.
Dundee United kept up their astonishing run of form with a sixth straight victory to move into fourth place, as a Jon Daly double and Scott Robertson strike sealed a 3-0 success at home to Dunfermline.
Hearts booked their place in the top six as a Rudi Skacel brace and Ryan McGowan opener saw off struggling Aberdeen 3-0.
Steven Thompson scored twice to help St Mirren beat Kilmarnock 4-2 and end a run of 11 games without a win.