The first half was a fine showcase of passing football that saw Pompey cruise into a commanding lead.
Meanwhile, the second period at Glanford Park saw the visitors have to display their battling qualities to secure three points.
And that is exactly what happened, with a 2-1 victory maintaining their unbeaten record on the road.
Tom Naylor and Gareth Evans both netted before the break, only for Lee Novak's strike to ensure a nervy finale.
But Pompey came through the tense closing stages and Kenny Jackett felt that his side’s performance warranted a maximum haul.
The Blues boss said: “I thought we deserved the victory, although there were a succession of free-kicks after they got one back.
“Scunthorpe are a big team – probably the biggest side that we’ve played so far in this division. We knew the ball would be coming into our box.
"In the end, though, I thought we produced a good offensive display and also a good defensive display."
“But we dealt with it very well in that particular period and if there’s any criticism, it’s that we didn’t get the third goal we perhaps needed at the start of the second half.
“In the end, though, I thought we produced a good offensive display and also a good defensive display.
“Oli Hawkins gave us a platform to play off and we were able to capitalise on that by scoring some goals.
“We looked a good side generally and you could see that our confidence is constantly growing going forwards.
“We came here 12 months ago and lost 2-0 to an established top six side, but we’ve made up the ground since then.”
Evans and Jamal Lowe both hobbled off during the second half, although Jackett was not overly concerned.
He said: “I think they’re knocks more than anything and they might need a bit of treatment on Sunday, but I fully expect them to be fine for training on Monday.
“With the way things are going for us at the moment, they’ll both want to make sure they’re on the pitch at Fratton Park against Walsall.”