Ross County can look forward to another season in the Scottish Premiership after beating Motherwell 2-1 at Fir Park on the final day.
John Hughes' team needed a point to secure safety but fell behind to an early Sam Foley goal before Iain Vigurs and Michael Gardyne turned it round in the second half.
A Mitch Pinnock double earned Kilmarnock a 2-0 win at Hamilton Accies, whose relegation to the Championship was confirmed after seven years in the top flight. Killie now face Dundee in the play-off final on Thursday May 20 and Monday May 24.
St Mirren finished seventh in the Premiership table after drawing 0-0 with Dundee United in Paisley in their final fixture of 2020/21.
