Adam Armstrong scored twice as Blackburn returned to winning ways with a 2-1 triumph at Portsmouth.Armstrong fired the promotion chasers to a first victory in three matches three minutes from time after Conor Chaplin had cancelled out his first half opener.The visitors finished with 10 men after Lewis Travis was sent off in stoppage time for a shocking challenge on Nathan Thompson.Blackburn had the better of the early exchanges and home goalkeeper Luke McGhee reacted smartly to deny Dominic Samuel with his legs.Newcastle loanee Armstrong's classy 23rd minute finish after Charlie Mulgrew had flicked on Richie Smallwood's cross gave Blackburn the lead.Pompey captain Brett Pitman and on loan Tottenham defender Anton Walkes both went close for the south coast side before the break.Chaplin looked to have rescued Pompey a point by heading his second goal in four days early in the second half.But Armstrong had the final word when he rammed home from close range after catching the home defence cold.