Kyle Lafferty scored a first-half hat-trick as Kilmarnock moved out of the relegation zone with a 3-0 victory over Dundee United at Rugby Park.
Ross County now occupy the relegation play-off place after going down 3-1 to St Mirren in Dingwall despite leading at half-time through Jordan White. Lee Erwin, Ilkay Durmus and Jamie McGrath (penalty) turned things round.
Bottom club Hamilton Accies were beaten 1-0 by Motherwell at the Foys Stadium. Mark O'Hara scored the only goal after Accies had Ronan Hughes sent off.
Champions Rangers were held to a 1-1 draw by St Johnstone at McDiarmid Park. Scott Wright gave the visitors the lead but Liam Craig equalised with a stoppage-time penalty.
Leigh Griffiths also netted in injury time as Celtic drew 1-1 with Aberdeen at Pittodrie after the Dons had gone in front through Lewis Ferguson.
Hibernian strengthened their grip on third place thanks to a 2-1 win over Livingston at Easter Road. Kevin Nisbet and Martin Boyle (penalty) were on target before Jay Emmanuel-Thomas pulled one back from the spot.