Lewis Mason chatted with Scunthorpe Telegraph sports reporter Paul Crute ahead of Pompey's League One trip to Glanford Park.
Here's what he had to say about the Iron’s chances against the table-topping Blues...
There have been signs of improvement in recent weeks.
The victory over Bristol Rovers last weekend was a first League One win in seven games.
That came after the FA Cup triumph against Burton Albion and coming back from 3-0 down to draw 3-3 when Oxford United visited prior to that.
What the past two or three weeks have done is bring the confidence back.
There are some small shoots of recovery that have been shown.
Issues have come in defence this season.
Whether it's individual errors or as a collective, the ball just does not seem to be kept out of the back of the net.
Notts County are the only team to have conceded more than goals in the top four divisions of English football so far this seasons.
Injuries in the back four have not helped, which has meant the rearguard hasn't been a settled line.
Even if you get to 2-0 or 3-0 up, you don't feel safe.
Scunthorpe have conceded three against Luton, three against Wycombe, four against Plymouth and five against Fleetwood. The defence has been a problem.
In the past couple of games they've only conceded the one, but three seems to be the norm at the moment.
Looking ahead to the game against Portsmouth I think most people would take a draw, considering where they are in the league.
Ryan Colclough would have been one of the main threats.
But he came off with a serious knee injury against Bristol Rovers and will be a big miss.
Striker Lee Novak has been putting in the goals recently, he's got three in his last four.
After managing to get rid of the niggling injuries from last season, he looks a lot leaner, a lot fitter.
Novak has been in fine form in front of goal of late, so he is one of the main threats.
Andy Dales is likely to play as well and could be a threat.
The forward joined from non-league side Mickleover Sports during in the summer.
Dales is one of those players who doesn't seem to have any fear, is willing to run at players and take them on.
He's got a couple of goals to his name, I'd say Dales and Novak are going to be the two main threats.