Blackburn strengthened their promotion charge with a comfortable 3-0 victory over Blackpool.Bradley Dack broke the deadlock in first-half stoppage-time and two second-half goals from in-form Adam Armstrong settled proceedings as the league leaders remain five points ahead of second-placed Shrewsbury and extended their unbeaten run to 16 matches.Former Rovers striker Nathan Delfounso had the gilt-edge chance during the early exchanges but goalkeeper David Raya brilliantly tipped over his close-range effort.They were made to pay at the end of the half when Charlie Mulgrew's sumptuous free-kick was glanced home by Dack at the near post for his 15th goal of the campaign.Armstrong put the contest to bed after 69 minutes with a stunning curling effort from 25 yards following good work from Dack to set him up. Blackpool almost halved the deficit but striker Danny Graham headed Curtis Tilt's looping header off the line. Armstrong added gloss to the scoreline by slotting home Elliott Bennett's low cross for his seventh Blackburn goal and help his side move eight points clear of third-placed Wigan.