Dumbarton held on to beat Hibernian 3-2 on Saturday as they completed a home double over the Easter Road men this season.
Kevin Cawley, Christian Nade and Darren Barr were all on target for Stephen Aitken's side before Liam Henderson and Farid El Alagui reduced the deficit.
Rangers are now 11 points clear in the Ladbrokes Championship after Harry Forrester's late goal saw them defeat St Mirren 1-0 at Ibrox.
Third-placed Falkirk are just two points behind Hibs following their 3-1 home victory over Queen of the South. Chris Higgins gave Queens a half-time lead but John Baird, Andy Dowie's own goal and Blair Alston turned things round.
Raith Rovers strengthened their grip on fourth spot by beating Morton 3-2 at Stark's Park. Declan McManus twice equalised after Rory McKeown and Aidan Connolly had netted for Rovers but Ryan Hardie grabbed a last-minute winner.
Livingston moved seven points clear of bottom club Alloa thanks to a 3-1 victory at the Indodrill Stadium. Jackson Longridge, Jordan White and Sam Stanton scored for Livi, with Michael Duffy netting for Alloa.