Pompey make their longest trip of the season when they head to the north-west to take on Carlisle on Saturday (3pm kick-off).
John Mousinho’s side will be aiming to at least maintain the four-point gap they currently hold over second spot.
There was a celebratory mood in Cumbria at the end of last season, as United secured promotion to League One following nine successive years in the basement.
They ended in fifth position before beating Bradford – after extra-time – over two legs and seeing off Stockport at Wembley.
That latter success was achieved on penalties following a 1-1 draw, with Blues midfielder Owen Moxon among those to score from the spot.
But Paul Simpson’s men have struggled at a higher level and currently find themselves at the foot of the table.
They are 11 points adrift of the safety line and head into this weekend’s contest on the back of five straight defeats.
Carlisle did put up a fight when they visited Fratton Park back in October, however, and it took a stoppage-time Conor Shaughnessy header to secure three points for Pompey.
Fans will have fond memories of the last trip to Brunton Park in 2017, when Gary Roberts, Amine Linganzi and Jack Whatmough netted in a 3-0 win en route to promotion.
It was announced earlier in the week that Terry Devlin (shoulder), Tom McIntyre (ankle) and Joe Morrell (knee) are all likely to miss the remainder of the season.
The trio join Tino Anjorin (hamstring), Josh Dockerill (knee), Regan Poole (knee), Alex Robertson (hamstring), Ben Stevenson (knee) and Zak Swanson (groin) on the sidelines.
Carlisle are without Joshua Kayode (calf) and Georgie Kelly (knee), while Jack Diamond (ankle) is also a doubt.
HEAD TO HEAD
Pompey: 18 wins
Carlisle: 13 wins
On the road
Pompey: 4 wins
Carlisle: 10 wins
Fans can longer buy tickets direct from Pompey and there are only a small number still available to buy at Carlisle on the day of the game, when prices increase by £3.
Click here for a guide to visiting Brunton Park that has been produced by the home club.
Overseas subscribers and match pass holders can watch all the action live, with replays and accompanying commentary.
There will be post-match reaction on the website and our official YouTube channel, with highlights to follow on Sunday.
ALSO IN LEAGUE ONE
All games kick-off at 3pm
Barnsley v Leyton Orient
Blackpool v Oxford
Bristol Rovers v Burton
Cambridge v Cheltenham
Derby v Shrewsbury
Lincoln v Fleetwood
Northampton v Bolton
Port Vale v Stevenage
Reading v Charlton
Wigan v Exeter
Wycombe v Peterborough
LAST AWAY MEETING