Greg Halford's header rescued a point for Portsmouth and dented Preston's hopes of Championship survival.
Eddie Johnson shot wide from 15 yards for the visiting team but the American later played in Iain Hume to slot home his sixth goal in as many games.
Hume and Keith Treacy tested Jamie Ashdown before Pompey equalised against the run of play when Halford converted Hayden Mullins' corner.
The result leaves Preston seven points adrift of safety with six games left.
North End are next in action on Tuesday at Doncaster, who are nine points above them.
Phil Brown's team might have found themselves in an even worse position as they contemplate their trip to the Keepmoat Stadium.
Joel Ward was inches away from converting a David Nugent cross that would have put Pompey in front at Fratton Park.
Nugent also shot wide as the home team finished the game strongly.
However, PNE also had opportunities after Halford's goal and Ashdown did well to tip a strike from Hume around the post.