Craig Barr scored a stoppage-time winner as Dumbarton beat Arbroath 2-1 at Gayfield in the first leg of the Championship play-off semi-final.
Calum Gallagher's opener was cancelled out by Bobby Linn but Barr struck right at the end to give Stevie Aitken's side the lead going into Saturday's return match.
Alloa Athletic took a big step towards the final with a 2-0 first-leg victory over Raith Rovers at the Indodrill Stadium, courtesy of goals from Ross Stewart and Iain Flannigan before the visitors had Iain Davidson sent off.
In the League 1 play-off semi-final, it's advantage Peterhead after Mason Robertson scored the only goal in a 1-0 success at Stirling Albion.