Pompey moved up two places in the table, despite being held at home by Fleetwood.
They had to battle from behind after Barrie McKay struck for the in-form visitors, with Sean Raggett sending a header looping into the net.
Harry Souttar's own-goal gave Kenny Jackett's side the lead after the break, but the same player then nodded the equaliser to ensure a 2-2 draw.