Falkirk moved to within two points of Hibernian thanks to a 1-0 win over Morton at Cappielow in the Ladbrokes Championship.
John Baird got the only goal for the third-placed Bairns after 27 minutes as the home side's play-off hopes were dealt a blow.
Raith Rovers moved into the top four after beating Livingston 2-0 at Stark's Park with goals from Mark Stewart and Aidan Connolly.
Lawrence Shankland was the matchwinner as St Mirren moved five points clear of Dumbarton by beating the Sons 1-0 in Paisley.
Leaders Rangers are away to Queen of the South on Sunday while promotion rivals Hibernian are at home bottom club Alloa, with both games live on Sky Sports.