There is plenty at stake at both ends of the League One table when visit Swindon this evening (6pm kick-off).
A run of three games without a win has seen the Blues drop just outside of the play-off places with five fixtures remaining.
Their hosts, meanwhile, are desperate to remain in the division, although time is running out to preserve their third tier status.
In fact, the Robins – who are bottom of the table – could be relegated tonight if they lose and both AFC Wimbledon and Wigan win their matches.
The Wiltshire outfit have lost each of their past five games to leave them seven points adrift of safety.
And a 4-1 defeat at Plough Lane on Saturday led to John Sheridan stepping down as manager, having only replaced Richie Wellens in November.
His assistant Tommy Wright has been placed in charge for the remainder of the campaign, working alongside Lee Peacock from the academy.
Relegation would ensure an immediate return to League Two, with Swindon claiming the title – pipping Crewe on the points-per-game method – last term.
Pompey do not have fond memories of their last competitive trip to the County Ground, with a 5-0 defeat ensuring a miserable first day of 2013.
But goals from Ronan Curtis and Ellis Harrison ensured a 2-0 victory when the sides met on the south coast a couple of months ago.
Alex Bass (foot), Ben Close (groin), Ellis Harrison (knee), Jordy Hiwula (ankle) and Michael Jacobs (knee) are all still sidelined.
Jack Whatmough starts a four-match ban following his second red card of the season at MK Dons on Saturday, while there are doubts over the fitness of Lee Brown (hamstring) and Andy Cannon (back).
Mathieu Baudry, Zeki Fryers, Rob Hunt, Ellis Iandolo (all hamstring), Dion Conroy (Achilles) and Akin Odimayo (knee) are all in the Swindon treatment room.
Paul Caddis (hamstring) could also miss out, but Brett Pitman is likely to feature against his former club.
VIEW FROM THE DRESSING ROOM
Read the thoughts of Danny Cowley ahead of the game.
HEAD TO HEAD
Pompey: 24 wins
Swindon: 28 wins
At County Ground
Pompey: 9 wins
Swindon: 18 wins
Referee: Ben Toner
Assistants: Stephen Brown and Garry Maskell
Fourth Official: Michael Chard
Supporters in the UK can watch the action live – with graphics, commentary and replays – by purchasing a match pass for £10.
Please note that subscribers based in the UK and Ireland will still need to purchase a match pass in order to watch the game live.
There will be post-match reaction on the website and our official YouTube channel, with highlights to follow on Wednesday.
ALSO IN LEAGUE ONE
Games kick-off at 7pm unless stated
Accrington v Doncaster
AFC Wimbledon v Oxford
Bristol Rovers v MK Dons
Burton v Lincoln
Northampton v Ipswich
Rochdale v Blackpool
Shrewsbury v Wigan
Fleetwood v Crewe (7.45pm)
Hull v Sunderland (7.45pm)
Peterborough v Gillingham (7.45pm)
Plymouth v Charlton (7.45pm)