Goals from Steve Torpey and a tasty freekick from Jamie McCombe were enough to dispatch the Division Two side and now the Humberside club will make the long trip south to Fratton Park.
They did it the hard way; They defeated Shrewsbury Town, who famously eliminated Everton 12 months ago, and needed a replay and penalties to squeeze past fallen giants Sheffield Wednesday in the second round.
Scunthorpe United have been almost a permanent fixture in the basement league over the last twenty years. Alex Calvo-Garcia's goal in the 1999 play-off final against Leyton Orient was enough to launch the Iron into Division Two, but they struggled badly and lasted only a season.
Since then, they have gone well in the Third and made the play-offs, where they were foiled by Lincoln City and Simon Yeo. So far, Scunny are a dissapointing Fourteenth in the league, but they have the talent to cause an over-confifent Pompey problems. One player Pompey fans might remember is Peter Beagrie - he no longer does the flips, but he's still a very real threat for the opposition.