Dumbarton advanced to the semi-finals of the Irn-Bru Cup on Saturday with a 2-0 triumph over League One Raith.The Sons made a positive start and were rewarded in the 19th minute when Chris McLaughlin prodded home the opener from a corner.Alistair Roy pounced on a defensive error to double the Championship side's advantage four minutes after the restart.The margin of victory might have been greater, but Tom Walsh's 57th-minute penalty was saved by Graeme Smith, after Greig Spence had been sent off for handling the ball on the line.