Livingston clinched the Ladbrokes League 1 title with four games to spare thanks to a 2-1 win over Alloa Athletic on Saturday.
David Hopkin's side needed just a point to seal the championship against their closest challengers but goals from Scott Pittman and Jackson Longridge saw them end the Wasps' 10-match unbeaten run, with Dylan Mackin netting for the visitors.
Today's win at the Tony Macaroni Arena marks an immediate return to the Ladbrokes Championship for Livingston, who were relegated last season.
Elsewhere in League 1, Airdrieonians leapfrogged Brechin City in the play-off places following a 3-1 win at the Excelsior Stadium.
Queen's Park kept their top-four ambitions alive with a 2-0 victory against second-bottom Peterhead at Hampden.
Albion Rovers are just three points outside the top four after beating Stranraer 3-0 at the Exsel Group Stadium.
Bottom club Stenhousemuir defeated East Fife 3-1 at Ochilview to close the gap on Peterhead to just two points as the visitors slipped to fifth.