Aberdeen have moved to just one point behind league leaders Celtic after a 1-0 win against third-placed Hearts.
Jordan McGhee gave away a late penalty which Adam Rooney scored to give the Dons the points.
At the other end of the table, Kilmarnock dropped into the relegation playoff place after an Iain Vigurs brace gave Inverness Caledonian Thistle victory.
Motherwell took full advantage of Killie's loss by beating Dundee 3-1 to rise to eighth. Early goals from Scott McDonald and Louis Moult were enough to claim victory, with Gary Harkins scoring a consolation for the Dee in the second half.
Dundee United's hopes of avoiding the drop took yet another blow after Kris Doolan's second-half winner for Partick Thistle left them nine points from safety.
Finally, mid-table side Ross County leapfrogged Hamilton Academical into fourth after two goals in the last five minutes gave them a 3-1 victory.
Celtic play St Johnstone at McDiarmid Park tomorrow.
Results in full: Aberdeen 1-0 Hearts (0-0), Dundee United 0-1 Partick Thistle (0-0), Hamilton Academical 1-3 Ross County (1-0), Inverness Caledonian Thistle 2-1 Kilmarnock (2-0), Motherwell 3-1 Dundee (2-0)
