Pompey eased to victory over Accrington, despite playing with 10 men for most of the contest.
The 4-0 success at Fratton Park ensured the gap to the play-off places closed to just seven points.
George Hirst opened the scoring, only for Marcus Harness to be dismissed for a challenge on Ross Sykes.
An impressive victory was then wrapped up when Ryan Tunnicliffe capitalised on good work from Aiden O'Brien.