Bradley Dack struck twice as Blackburn extended their lead at the top of League One to four points thanks to a 3-0 win at AFC Wimbledon.Dack opened the scoring on the half-hour with his 13th of the season, heading over stranded Dons goalkeeper George Long from Jack Payne's deep cross. The goal was given despite Deji Oshilaja's attempted goalline clearance.Tony Mowbray's side almost extended their lead seven minutes later, as Charlie Mulgrew's deflected free-kick hit the side netting.AFC Wimbeldon had chances of their own with Jon Meades and Andy Barcham going close in the opening half.And they had further opportunities after the break as Lyle Taylor and Harry Forrester went close for the Londoners, who remain just two points above the relegation zone.However, Blackburn made them pay as Elliott Bennett scored a spectacular solo effort from 25 yards for his first goal since April.Dack then chipped Long following fantastic play out wide by Danny Graham to earn the visitors their fourth consecutive win.